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21.A Apply access control concepts, methodologies, and techniques 
31.A.1 Application control concepts and principles (e.g. discretionary/mandatory, segregation/separation of duties, rule of least privilege) 
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5DAC 
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7Known as Identity-based Access control - The type of discretionary access control (DAC) that is based on an individual's identity 
8With Discretionary Access Control, the subject has authority, within certain limitations, to specify what objects can be accessible.  
9For example, access control lists can be used. This type of access control is used in local, dynamic situations where the subjects must have the discretion to specify what resources certain users are permitted to 
10access.  
11When a user, within certain limitations, has the right to alter the access control to certain objects, this is termed as user-directed discretionary access control. In some instances, a hybrid approach is used, which 
12combines the features of user-based and identity-based discretionary access control. 
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15The read privilege is the most problematic privilege regarding information flows. The privilege essentially allows the subject to create a copy of the object in memory. 
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19Non-DAC -> more DAC than MAC 
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21Non-DAC access control is when a central authority determines what subjects can have access to what objects based on the organizational security policy. Centralized access control is not an existing 
22security model. 
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25•         RBAC - include Role Based Access Control (RBAC) and Rule Based Access Control (RBAC or RuBAC).   RABC being a subset of NDAC, it was easy to eliminate RBAC as it was covered under NDAC already.  
26•         TBAC – Task based, Time – Sequence - Dependencies 
27•         ORCON – Originator controlled – owner controls the lifecycle 
28•         DRM – digital rights management, intellectual content  
29•         UCON – Usage controlled – frequency of access. 
30•         Rule-based - is when you have ONE set of rules applied uniformly to all users.  A good example would be a firewall at the edge of your network.  A single rule based is applied against any packets 
31received from the internet. 
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34MAC - is a very rigid type of access control.  The subject must dominate the object and the subject must have a Need To Know to access the information.  Objects have labels that indicate the sensitivity 
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36(classification) and there is also categories to enforce the Need To Know (NTK). 
37-         Classifications and labels 
38-         Confidential, Secret, Top Secret 
39-         A Sensitivity label must contain at least one classification and one category set.  
40-         Category set = compartment set = The sensitivity label must contain at least one Classification and at least one Category Set/Compartment set, but it is common in some environments for a single item 
41to belong to multiple category sets. The list of all the categories to which an item belongs is called a compartment set or category set. 
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44MAC provides high security by regulating access based on the clearance of individual users and sensitivity labels for each object.  Clearance levels and sensitivity levels cannot be modified by individual users -- 
45for example, user Joe (SECRET clearance) cannot reclassify the "Presidential Doughnut Recipe" from "SECRET" to "CONFIDENTIAL" so that his friend Jane (CONFIDENTIAL clearance) can read it.  The administrator 
46is ultimately responsible for configuring this protection in accordance with security policy and directives from the Data Owner. 
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49A Sensitivity label must contain at least one classification and one category set. 
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54In a Mandatory Access Control (MAC) environment active entities that take actions are called Subjects and the passive entities that are acted upon are known as Objects.  A Subject could be a users, a 
55programs, and processes where Objects would be files, directories, print queue, devices, windows, and sockets.  
56All of those listed in the answer are defined as Objects.  
57Note: Some devices could be considered active entities such as smart card readers and some devices such as electrical switches, disc drives, relays, and mechanical components connected to a computer system 
58may also be included in the category of objects [NCSC88].  
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61This makes this answer the best based on the other answers. 
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64•   Lattice-based access control - In this type of control, a lattice model is applied. To apply this concept to access control, the pair of elements is the subject and object, and the subject has to have an upper 
65bound equal or higher than the object being accessed. 
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68NOTE FROM CLEMENT: 
69Lot of people tend to confuse MAC and Rule Based Access Control. 
70Mandatory Access Control must make use of LABELS.  If there is only rules and no label, it cannot be Mandatory Access Control.  This is why they call it Non Discretionary Access control (NDAC).  
71There are even books out there that are WRONG on this subject.  Books are sometimes opiniated and not strictly based on facts.  
72In MAC subjects must have clearance to access sensitive objects.  Objects have labels that contain the classification to indicate the sensitivity of the object and the label also has categories to enforce the need to 
73know. 
74Today the best example of rule based access control would be a firewall.   All rules are imposed globally to any user attempting to connect through the device.  This is NOT the case with MAC. 
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80Bell Lapadula  
81The Bell-LaPadula model is a formal model dealing with confidentiality. 
82The Bell-LAPadula model is also called a multilevel security system because users with different clearances use the system and the system processes data with different classifications.   Developed by the US 
83Military in the 1970s. 
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86The Bell–LaPadula Model (abbreviated BLP) is a state machine model used for enforcing access control in government and military applications.   It was developed by David Elliott Bell and Leonard J. LaPadula, 
87subsequent to strong guidance from Roger R. Schell to formalize the U.S. Department of Defense (DoD) multilevel security (MLS) policy.  The model is a formal state transition model of computer security policy 
88that describes a set of access control rules which use security labels on objects and clearances for subjects. Security labels range from the most sensitive (e.g."Top Secret"), down to the least sensitive (e.g., 
89"Unclassified" or "Public"). 
90The Bell–LaPadula model focuses on data confidentiality and controlled access to classified information, in contrast to the Biba Integrity Model which describes rules for the protection of data integrity.  In this 
91formal model, the entities in an information system are divided into subjects and objects.   
92The notion of a "secure state" is defined, and it is proven that each state transition preserves security by moving from secure state to secure state, thereby inductively proving that the system satisfies the 
93security objectives of the model. The Bell–LaPadula model is built on the concept of a state machine with a set of allowable states in a computer network system. The transition from one state to another state is 
94defined by transition functions. 
95A system state is defined to be "secure" if the only permitted access modes of subjects to objects are in accordance with a security policy. To determine whether a specific access mode is allowed, the clearance 
96of a subject is compared to the classification of the object (more precisely, to the combination of classification and set of compartments, making up the security level) to determine if the subject is authorized for 
97the specific access mode.  
98The clearance/classification scheme is expressed in terms of a lattice. The model defines two mandatory access control (MAC) rules and one discretionary access control (DAC) rule with three security properties: 
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110The Star (*) property (confinement property) rule of the Bell-LaPadula model says that subjects NO WRITE DOWN, this would compromise the confidentiality of the information if someone at the 
111secret layer would write the object down to a confidential container for example.   
112The Simple Security (ss) Property rule states that the subject NO READ UP which means that a subject at the secret layer would not be able to access objects at Top Secret for example.  
113The Bell-LaPadula model, mostly concerned with confidentiality, was proposed for enforcing access control in government and military applications. It supports mandatory access control by determining the 
114access rights from the security levels associated with subjects and objects. It also supports discretionary access control by checking access rights from an access matrix. The Biba model, introduced in 1977, the 
115Sutherland model, published in 1986, and the Brewer-Nash model, published in 1989, are concerned with integrity. 
116Tranquility principle - The tranquility principle of the Bell-LaPadula model states that the classification of a subject or object does not change while it is being referenced. There are two forms to the tranquility 
117principle: the "principle of strong tranquility" states that security levels do not change during the normal operation of the system and the "principle of weak tranquility" states that security levels do not change 
118in a way that violates the rules of a given security policy. Another interpretation of the tranquility principles is that they both apply only to the period of time during which an operation involving an object or 
119subject is occurring. That is, the strong tranquility principle means that an object's security level/label will not change during an operation (such as read or write); the weak tranquility principle means that an 
120object's security level/label may change in a way that does not violate the security policy during an operation.  
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123Clark-Wilson model addresses integrity. It incorporates mechanisms to enforce internal and external consistency, a separation of duty, and a mandatory integrity policy. 
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126In the Clark-Wilson model, the subject no longer has direct access to objects but instead must access them through programs (well -formed transactions). 
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129The Clark-Wilson model uses separation of duties, which divides an operation into different parts and requires different users to perform each part. This prevents authorized users from making unauthorized 
130modifications to data, thereby protecting its integrity. 
131The Clark-Wilson integrity model provides a foundation for specifying and analyzing an integrity policy for a computing system. 
132The model is primarily concrned with formalizing the notion of information integrity. Information integrity is maintained by preventing corruption of data items in a system due to either error or malicious intent. 
133An integrity policy describes how the data items in the system should be kept valid from one state of the system to the next and specifies the capabilities of various principals in the system. The model defines 
134enforcement rules and certification rules. 
135The model’s enforcement and certification rules define data items and processes that provide the basis for an integrity policy. The core of the model is based on the notion of a transaction. 
136A well-formed transaction is a series of operations that transition a system from one consistent state to another consistent state. 
137In this model the integrity policy addresses the integrity of the transactions. 
138The principle of separation of duty requires that the certifier of a transaction and the implementer be different entities. 
139The model contains a number of basic constructs that represent both data items and processes that operate on those data items. The key data type in the Clark-Wilson model is a Constrained Data Item (CDI). An 
140Integrity Verification Procedure (IVP) ensures that all CDIs in the system are valid at a certain state. Transactions that enforce the integrity policy are represented by Transformation Procedures (TPs). A TP takes 
141as input a CDI or Unconstrained Data Item (UDI) and produces a CDI. A TP must transition the system from one valid state to another valid state. UDIs represent system input (such as that provided by a user or 
142adversary). A TP must guarantee (via certification) that it transforms all possible values of a UDI to a “safe” CDI. 
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145Biba - The simple integrity axiom of the Biba access control model states that a subject at one level of integrity is not permitted to observe an object of a lower integrity (no read down). 
146BIBA addresses only the first rule of integrity. 
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149Least Privilege 
150Does not require: Ensuring that the user alone does not have sufficient rights to subvert an important process. 
151-         Least Functionality 
152In the real world, organizations are understaffed, people wear too many hats, separation of duties is seldom complete, development staff often supports production systems, IT staff often maintains production 
153data and access is often granted on the basis of least effort instead of least privilege and need to know. 
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164Separation of Duties  
165Preventive control 
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168Architecture 
169-         Trusted Computing Base 
170o        Reference Monitor – get requests and check if it was allowed. 
171o        Kernel – a collection of components of TCB. 
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1751.A.2 Account life cycle management (e.g. registration, enrolment, access control administration) 
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1781.A.3 Identification, authentication, authorization, and accounting methods 
179Authentication - is verification that the user's claimed identity is valid and is usually implemented through a user password at log-on time. 
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182Accountability would not include policies & procedures because while important on an effective security program they cannot be used in determing accountability. 
183Accountability  = access rules + audit trails + unique identifiers. 
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186Identification - act of a user professing an identity to a system, usually in the form of a log-on ID 
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189A continuous authentication provides protection against impostors who can see, alter, and insert information passed between the claimant and verifier even after the claimant/verifier authentication is 
190complete. This is the best protection against hijacking. Static authentication is the type of authentication provided by traditional password schemes and the strength of the authentication is highly 
191dependent on the difficulty of guessing passwords. The robust authentication mechanism relies on dynamic authentication data that changes with each authenticated session between a claimant and a verifier, 
192and it does not protect against hijacking. Strong authentication refers to a two-factor authentication (like something a user knows and something a user is). 
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195The important thing to remember is that Identity Management Solutions provides consistency, efficiency, usability, reliability and scalabilty. 
196FACEBOOK, TWEETER -> Any identity management system used in an environment where there are tens of thousands of users must be able to scale to support the volumes of data and peak transaction rates. 
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202BIOMETRIC: 
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204When used in physical control biometric Identification is performed by doing a one to many match.  When you submit your biometric template a search is done through a database of templates until the 
205matching one is found.  At that point your identity is revealed and if you are a valid employee access is granted. When used in logical controls the biometric template is used to either confirm or deny someone 
206identity.  For example if I access a system and I pretend to be user Nathalie then I would provide my biometric template to confirm that I really am who I pretend to be.  Biometric is one of the three 
207authentication factor (somethin you are) that can be use.  The other two are something you know and something you have.  
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210RETINA - least accepted, most expensive! 
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223IRIS pattern is considered lifelong. Unique features of the iris are: freckles, rings, rifts, pits, striations, fibers, filaments, furrows, vasculature and coronas. Voice, signature and retina patterns are more likely to 
224change over time, thus are not as suitable for authentication over a long period of time without needing re-enrollment. 
225Because the optical unit utilizes a camera and infrared light to create the images, sun light can impact the aperture so it must not be positioned in direct light of any type. Because the subject does not need to 
226have direct contact with the optical reader, direct light can impact the reader. 
227An Iris recognition is a form of biometrics that is based on the uniqueness of a subject's iris. A camera like device records the patterns of the iris creating what is known as Iriscode.  
228It is the unique patterns of the iris that allow it to be one of the most accurate forms of biometric identification of an individual. Unlike other types of biometics, the iris rarely changes over time. Fingerprints can 
229change over time due to scaring and manual labor, voice patterns can change due to a variety of causes, hand geometry can also change as well. But barring surgery or an accident it is not usual for an iris to 
230change. The subject has a high-resoulution image taken of their iris and this is then converted to Iriscode. The current standard for the Iriscode was developed by John Daugman. When the subject attempts to 
231be authenticated an infrared light is used to capture the iris image and this image is then compared to the Iriscode. If there is a match the subject's identity is confirmed. The subject does not need to have direct 
232contact with the optical reader so it is a less invasive means of authentication then retinal scanning would be. 
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235When a biometric system is used for access control, the most important error is the false accept or false acceptance rate, or Type II error, where the system would accept an impostor.  
236A Type I error is known as the false reject or false rejection rate and is not as important in the security context as a type II error rate.   A type one is when a valid company employee is rejected by the system and 
237he cannot get access even thou it is a valid user.  
238The Crossover Error Rate (CER) is the point at which the false rejection rate equals the false acceptance rate if your would create a graph of Type I and Type II errors.  The lower the CER the better the device 
239would be.  
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242EER or CER - Equal error rate or crossover error rate (EER or CER): the rate at which both accept and reject errors are equal. The value of the EER can be easily obtained from the ROC curve. The EER is a quick 
243way to compare the accuracy of devices with different ROC curves. In general, the device with the lowest EER is most accurate.  
244The Crossover Error Rate (CER) is the point where false rejection rate (type I error) equals the false acceptance rate (type II error). The lower the CER, the better the accuracy of the device. At the time if this 
245writing, response times and accuracy of some devices are: 
246System type        Response time     Accuracy (CER)  
247Fingerprints        5-7 secs.            5%  
248Hand Geometry    3-5 secs.            2%  
249Voice Pattern      10-14 secs.         10%  
250Retina Scan        4-7 secs.            1.5%  
251Iris Scan            2.5-4 secs.          0.5%  
252The term EER which means Equal Error Rate is sometimes use instead of the term CER.  It has the same meaning. 
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256In the context of Biometric Authentication almost all types of detection permit a system's sensitivity to be increased or decreased during an inspection process. If the system's sensitivity is increased, such as in 
257an airport metal detector, the system becomes increasingly selective and has a higher False Reject Rate (FRR).  
258Conversely, if the sensitivity is decreased, the False Acceptance Rate (FAR) will increase.  
259Thus, to have a valid measure of the system performance, the CrossOver Error Rate (CER) is used. 
260The following are used as performance metrics for biometric systems: 
261False accept rate or false match rate (FAR or FMR): the probability that the system incorrectly matches the input pattern to a non-matching template in the database. It measures the percent of invalid inputs 
262which are incorrectly accepted. In case of similarity scale, if the person is imposter in real, but the matching score is higher than the threshold, then he is treated as genuine that increase the FAR and hence 
263performance also depends upon the selection of threshold value. 
264False reject rate or false non-match rate (FRR or FNMR): the probability that the system fails to detect a match between the input pattern and a matching template in the database. It measures the percent of 
265valid inputs which are incorrectly rejected. 
266Failure to enroll rate (FTE or FER): the rate at which attempts to create a template from an input is unsuccessful. This is most commonly caused by low quality inputs. 
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276Failure to capture rate (FTC): Within automatic systems, the probability that the system fails to detect a biometric input when presented correctly. 
277Template capacity: the maximum number of sets of data which can be stored in the system. 
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280Almost all types of detection permit a system's sensitivity to be increased or decreased during an inspection process. If the system's sensitivity is increased, such as in a biometric authentication system, the 
281system becomes increasingly selective and has a higher False Rejection Rate (FRR).  
282Conversely, if the sensitivity is decreased, the False Acceptance Rate (FRR) will increase. Thus, to have a valid measure of the system performance, the Cross Over Error (CER) rate is used.  The Crossover Error 
283Rate (CER) is the point at which the false rejection rates and the false acceptance rates are equal.  The lower the value of the CER, the more accurate the system. 
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286Throughput - The throughput rate is the rate at which individuals, once enrolled, can be processed and identified or authenticated by a biometric system.  
287Acceptable throughput rates are in the range of 10 subjects per minute.  
288Things that may impact the throughput rate for some types of biometric systems may include: 
289A concern with retina scanning systems may be the exchange of body fluids on the eyepiece.  
290Another concern would be the retinal pattern that could reveal changes in a person's health, such as diabetes or high blood pressure. 
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293Masquarading attacks - The only way to be truly positive in authenticating identity for access is to base the authentication on the physical attributes of the persons themselves (i.e., biometric identification). 
294Physical attributes cannot be shared, borrowed, or duplicated. They ensure that you do identify the person, however they are not perfect and they would have to be supplemented by another factor.  
295Some people are getting thrown off by the term Masquarade.  In general, a masquerade is a disguise. In terms of communications security issues, a masquerade is a type of attack where the attacker pretends to 
296be an authorized user of a system in order to gain access to it or to gain greater privileges than they are authorized for.  A masquerade may be attempted through the use of stolen logon IDs and passwords, 
297through finding security gaps in programs, or through bypassing the authentication mechanism.  Spoofing is another term used to describe this type of attack as well.    
298A UserId only provides for identification.  
299A password is a weak authentication mechanism since passwords can be disclosed, shared, written down, and more. 
300A smart card can be stolen and its corresponding PIN code can be guessed by an intruder. A smartcard can be borrowed by a friend of yours and you would have no clue as to who is really logging in using that 
301smart card.  
302Any form of two-factor authentication not involving biometrics cannot be as reliable as a biometric system to identify the person.  
303See an extract below from the HISM book volume 1 (Available on www.cccure.org in HTML format)  
304Biometric identifying verification systems control people. If the person with the correct hand, eye, face, signature, or voice is not present, the identification and verification cannot take place and the desired 
305action (i.e., portal passage, data, or resource access) does not occur. 
306As has been demonstrated many times, adversaries and criminals obtain and successfully use access cards, even those that require the addition of a PIN. This is because these systems control only pieces of 
307plastic (and sometimes information), rather than people. Real asset and resource protection can only be accomplished by people, not cards and information, because unauthorized persons can (and do) obtain 
308the cards and information. 
309Further, life-cycle costs are significantly reduced because no card or PIN administration system or personnel are required. The authorized person does not lose physical characteristics (i.e., hands, face, eyes, 
310signature, or voice), but cards and PINs are continuously lost, stolen, or forgotten. This is why card access systems require systems and people to administer, control, record, and issue (new) cards and PINs. 
311Moreover, the cards are an expensive and recurring cost. 
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314Authentication is based on three factor types: type 1 is something you know, type 2 is something you have and type 3 is something you are. Biometrics are based on the Type 3 authentication mechanism. 
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317Most effective from Best to worst: 
318Retina 
319Fingerprint 
320Hand Print  
321Voice pattern 
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331Keystroke  
332Signature 
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335Order of acceptance from most accepted to least accepted: 
336Keystroke 
337Signature 
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339Handprint 
340Fingerprint 
341Retina  
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344In biometrics, identification is a "one-to-many" search of an individual's characteristics from a database of stored images. 
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3481.B Determine identity and access management architecture 
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351Authentication, Authorization and Accounting - AAA 
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3531.B.1 Centralized 
354Here one entity (dept or an individual) is responsible for overseeing access to all corporate resources. 
355This type of administration provides a consistent and uniform method of controlling users access rights. 
356Example: RADIUS, TACACS and Diameter 
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3601.B.2 Decentralized 
361A decentralized access control administration method gives control of access to the people closer to the resources 
362In this approach, it is often the functional manager who assigns access control rights to employees. 
363Changes can happen faster through this type of administration because not just one entity is making changes for the whole organization. 
364There is a possibility for conflicts to arise that may not benefit the organization as because different managers and departments can practice security and access control in different ways. 
365There is a possibility of certain controls to overlap, in which case actions may not be properly proscribed or restricted. 
366This type of administration does not provide methods for consistent control, as a centralized method would. 
367MS Active Directory, OpenLDAP, etc.… 
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3701.B.3 Federated Identity 
371in information technology is the means of linking a person's electronic identity and attributes, stored across multiple distinct identity management systems.[1] 
372Related to federated identity is single sign-on (SSO), in which a user's single authentication ticket, or token, is trusted across multiple IT systems or even organizations. SSO is a subset of federated identity 
373management, as it relates only to authentication and is understood on the level of technical interoperability. 
374Technologies used for federated logon include SAML (Security Assertion Markup Language), OAuth and OpenID as well as proprietary standards. 
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3771.B.4 Access Control Protocols and Technologies: 
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389TACACS 
390The original TACACS, developed in the early ARPANet days, had very limited functionality and used the UDP transport.  
391In the early 1990s, the protocol was extended to include additional functionality and the transport changed to TCP. 
392It is a remote authentication protocol that is used to communicate with an authentication server commonly used in UNIX networks. TACACS allows a remote access server to communicate with an authentication 
393server in order to determine if the user has access to the network. TACACS is defined in RFC 1492, and uses (either TCP or UDP) port 49 by default. 
394TACACS allows a client to accept a username and password and send a query to a TACACS authentication server, sometimes called a TACACS daemon or simply TACACSD. TACACSD uses TCP and usually runs on 
395port 49. It would determine whether to accept or deny the authentication request and send a response back. The TIP (routing node accepting dial-up line connections, which the user would normally want to log 
396in into) would then allow access or not, based upon the response. In this way, the process of making the decision is "opened up" and the algorithms and data used to make the decision are under the complete 
397control of whomever is running the TACACS daemon. 
398A later version of TACACS introduced by Cisco in 1990 was called Extended TACACS (XTACACS). The XTACACS protocol was developed by and is proprietary to Cisco Systems. 
399TACACS+ and RADIUS have generally replaced TACACS and XTACACS in more recently built or updated networks. TACACS+ is an entirely new protocol and is not compatible with TACACS or XTACACS. TACACS+ 
400uses the Transmission Control Protocol (TCP) and RADIUS uses the User Datagram Protocol (UDP). Since TCP is connection oriented protocol, TACACS+ does not have to implement transmission control. RADIUS, 
401however, does have to detect and correct transmission errors like packet lost, timeout etc. since it rides on UDP which is connectionless. 
402RADIUS encrypts only the users' password as it travels from the RADIUS client to RADIUS server. All other information such as the username, authorization, accounting are transmitted in clear text. Therefore it is 
403vulnerable to different types of attacks. TACACS+ encrypts all the information mentioned above and therefore does not have the vulnerabilities present in the RADIUS protocol. 
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406TACACS+ - is an access control network protocol for routers, network access servers and other networked computing devices. 
407Unlike RADIUS and the predecessors of TACACS+ (TACACS and XTACACS), TACACS+ provides separate authentication, authorization and accounting services. Like RADIUS, TACACS and XTACACS, TACACS+ is an 
408open, publicly documented protocol. TACACS+ uses the TCP protocol and encrypts the entire packet (except the header). 
409TACACS+ ultimately derives from (but is not backwards-compatible with) TACACS, developed in 1984 for MILNET by BBN, a contractor for the U.S. Department of Defense. Originally designed as means to 
410automate logins, by which a person who was already authenticated on one host in the network could connect to another host on the same network without needing to authenticate again, TACACS is an open 
411(quasi-)standard, described by BBN's Brian Anderson in Internet Engineering Task Force (IETF) RFC 927. 
412Cisco Systems began supporting TACACS in its networking products in the late 1980s, eventually adding their own extensions to the protocol, which the company then called 'XTACACS' ('eXtended TACACS'). In 
413the simple (non-extended) form, Cisco's implementation was compatible with the original TACACS, while the extended form (XTACACS) was not. In 1993, with Cisco's assistance, Craig Finseth of the University of 
414Minnesota published a description of Cisco's extensions in IETF RFC 1492. 
415The protocol continued to evolve over the following years, and in 1996 became what Cisco called 'TACACS+', in which the individual tasks of authentication, authorization and accounting were separate 
416processes. Also, while the XTACACS and TACACS use UDP (port 49), TACACS+ uses TCP (but still port 49). Cisco's David Carrel and Lol Grant submitted TACACS+ v1.75 for IETF standards approval in October 1996, 
417followed by a revised version 1.78 in January 1998. The IETF draft expired in September 1998 without becoming an approved standard. 
418TACACS+ and RADIUS have generally replaced the older protocols. 
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421Whereas RADIUS combines authentication and authorization in a user profile, TACACS+ separates the two operations. Another difference is that TACACS+ uses the Transmission Control Protocol (TCP) while 
422RADIUS uses the User Datagram Protocol (UDP). 
423The extensions to the TACACS+ protocol provide for more types of authentication requests and more types of response codes than were in the original specification. 
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426TACACS has been through three generations: TACACS, Extended TACACS (XTACACS), and TACACS+. 
427TACACS combines its authentication and authorization processes, 
428XTACACS separates authentication, authorization, and auditing processes and 
429TACACS+ is XTACACS with extended two-factor user authentication. 
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440RADIUS -  
441A Network Access Server (NAS) operates as a client of RADIUS.  The client is responsible for passing user information to designated RADIUS servers, and then acting on the response which is returned. RADIUS 
442servers are responsible for receiving user connection requests, authenticating the user, and then returning all configuration information necessary for the client to deliver service to the user. RADIUS 
443authentication is based on provisions of simple username/password credentials. These credentials are encrypted by the client using a shared secret between the client and the RADIUS server. OIG 2007, Page 
444513 RADIUS incorporates an authentication server and can make uses of both dynamic and static passwords.  
445Since it uses the PAP and CHAP protocols, it also incluses static passwords. 
446RADIUS is an Internet protocol. RADIUS carries authentication, authorization, and configuration information between a Network Access Server and a shared Authentication Server. RADIUS features and functions 
447are described primarily in the IETF (International Engineering Task Force) document RFC2138.  
448The term " RADIUS" is an acronym which stands for Remote Authentication Dial In User Service. 
449The main advantage to using a RADIUS approach to authentication is that it can provide a stronger form of authentication. RADIUS is capable of using a strong, two-factor form of authentication, in which users 
450need to possess both a user ID and a hardware or software token to gain access.  
451Token-based schemes use dynamic passwords. Every minute or so, the token generates a unique 4-, 6- or 8-digit access number that is synchronized with the security server. To gain entry into the system, the 
452user must generate both this one-time number and provide his or her user ID and password.  
453Although protocols such as RADIUS cannot protect against theft of an authenticated session via some realtime attacks, such as wiretapping, using unique, unpredictable authentication requests can protect 
454against a wide range of active attacks.  
455RADIUS supports dynamic passwords and challenge/response passwords.  
456RADIUS allows the user to have a single user ID and password for all computers in a network. 
457In response to an access-request from a client, a RADIUS server returns one of three authentication responses: access-accept, access-reject, or access-challenge, the latter being a request for additional 
458authentication information such as a one-time password from a token or a callback identifier. 
459Diameter uses SCTP or TCP while RADIUS typically uses UDP as the transport layer. As of 2012, RADIUS can also use TCP or TLS as the transport layer. 
460•    A RADIUS server can act as a proxy server, forwarding client requests to other authentication domains.  
461•    Most of RADIUS clients have a capability to query secondary RADIUS servers for redundancy.  
462•    Most RADIUS servers have built-in database connectivity for billing and reporting purposes. 
463
464
465
466Kerberos 
467addresses the confidentiality and integrity of information.  
468It also addresses primarily authentication but does not directly address availability. 
469
470
471Kerberos depends on Secret Keys or Symmetric Key cryptography. Kerberos a third party authentication protocol. It was designed and developed in the mid 1980's by MIT. It is considered open source but is 
472copyrighted and owned by MIT. It relies on the user's secret keys.  The password is used to encrypt and decrypt the keys.  
473
474
475
476Kerberos is a trusted, credential-based, third-party authentication protocol that was developed at MIT and that uses symmetric (secret) key cryptography to authenticate clients to other entities on a network for 
477access to services.  
478Kerberos does not use X.509 certificates, which are used in public key cryptography. 
479
480
481Kerberos DOES NOT use a database to keep a copy of all users' public keys.  
482Kerberos is a trusted, credential-based, third-party authentication protocol that uses symmetric (secret) key cryptography to provide robust authentication to clients accessing services on a network.  
483One weakness of Kerberos is its Key Distribution Center (KDC), which represents a single point of failure. The KDC contains a database that holds a copy of all of the symmetric/secret keys for the principals. 
484
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487
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494
495The server also checks the authenticator and, if that timestamp is valid, it provides the requested service to the client. 
496Even if the user principal is present in a ticket and only the application server can extract and possibly manage such information (since the ticket is encrypted with the secret key of the service), this is not enough 
497to guarantee the authenticity of the client.  
498An impostor could capture (remember the hypothesis of an open and insecure network) the ticket when it is sent by a legitimate client to the application server, and at an opportune time, send it to 
499illegitimately obtain the service.  
500On the other hand, including the IP addresses of the machine from where it is possible to use it is not very useful: it is known that in an open and insecure network addresses are easily falsified. To solve the 
501problem, one has to exploit the fact that the client and server, at least during a session have the session key in common that only they know (also the KDC knows it since it generated it, but it is trusted by 
502definition!!!).  
503Thus the following strategy is applied: along with the request containing the ticket, the client adds another packet (the authenticator) where the user principal and time stamp (its at that time) are included and 
504encrypts it with the session key; the server which must offer the service, upon receiving this request, unpacks the first ticket, extracts the session key and, if the user is actually who he/she says, the server is able 
505to unencrypt the authenticator extracting the timestamp.  
506If the latter differs from the server time by less than 2 minutes (but the tolerance can be configured) then the authentication is successful. This underlines the criticality of synchronization between machines 
507belonging to the same realm.  
508
509
510STEP BY STEP: Principle P1 authenticates to the Key Distribution Center (KDC), principle P1 receives a Ticket Granting Ticket (TGT), and principle P1 requests a service ticket from the Ticket Granting Service (TGS) 
511in order to access the application server P2. 
512
513
514The Key Distribution Center (KDC) holds all users' and services' cryptographic keys. It provides authentication services, as well as key distribution functionality. The Authentication Service is the part of the KDC 
515that authenticates a principal.  
516
517
518A Kerberos ticket is issued by a trusted third party.  Is is an encrypted data structure that includes the service encryption key.  In that sense it is similar to a public-key certificate.  However, the ticket is not the 
519key.  
520Kerberos is Vulnerable to Password Guessing.   
521
522
523The Replay (Playback) Attack 
524A replay attack occurs when an intruder steals the packet and presents it to the service as if the intruder were the user. The user's credentials are there -- everything needed to access a resource. This is 
525mitigated by the features of the "Authenticator," which is illustrated in the picture below.  
526The Authenticator is created for the AS_REQ or the TGS_REQ and sends additional data, such as an encrypted IP list, the client's timestamp and the ticket lifetime. If a packet is replayed, the timestamp is 
527checked.  If the timestamp is earlier or the same as a previous authenticator, the packet is rejected because it's a replay.  In addition, the time stamp in the Authenticator is compared to the server time. It must 
528be within five minutes (by default in Windows).  
529Kerberos Authenticator to prevent replay attacks 
530The Authenticator mitigates the Possibility of a replay attack.  
531If the time skew is greater than five minutes the packet is rejected. This limits the number of possible replay attacks. While it is technically possible to steal the packet and present it to the server before the valid 
532packet gets there, it is very difficult to do.  
533It's fairly well known that all computers in a Windows domain must have system times within five minutes of each other. This is due to the Kerberos requirement.  
534
535
536
537SESAME - is an authentication and access control protocol, that also supports communication confidentiality and integrity.  It provides public key based authentication along with the Kerberos style 
538authentication, that uses symmetric key cryptography.  Sesame supports the Kerberos protocol and adds some security extensions like public key based authentication and an ECMA-style Privilege Attribute 
539Service.  The complete Sesame protocol is a two step process. In the first step, the client successfully authenticates itself to the Authentication Server and obtains a ticket that can be presented to the Privilege 
540
541
542
543
544
545
546
547
548Attribute Server.  In the second step, the initiator obtains proof of his access rights in the form of Privilege Attributes Certificate (PAC). The PAC is a specific form of Access Control Certificate as defined in the 
549ECMA-219 document. This document describes the extensions to Kerberos for public key based authentication as adopted in Sesame. 
550SESAME uses Attribute Certificate (AC) that allows for granular access control . It supports authentication, confidentiality but also authorization.  In environment with well defined roles and capability is an issue , 
551SESAME and PERMIS are role based single sign on technologies.   
552Secure European System for Applications in a Multi-Vendor Environment (Sesame) is a single-sign-on technology developed to extend Kerberos functionality and improve upon its weaknesses. Sesame uses 
553asymmetric and symmetric cryptographic technologies to authenticate subjects to network resources.  
554
555
556
557
558
559Vulnerable to Password Guessing. The Basic Mechanism in Sesame for strong authentication is as follow: 
560The user sends a request for authentication to the Authentication Server as in Kerberos, except that SESAME is making use of public key cryptography for authentication where the client will present his digital 
561certificate and the request will be signed using a digital signature. The signature is communicated to the authentication server through the preauthentication fields. Upon receipt of this request, the 
562authentication server will verifies the certificate, then validate the signature, and if all is fine the AS will issue a ticket granting ticket (TGT) as in Kerberos. This TGT will be use to communicate with the privilage 
563attribute server (PAS) when access to a resource is needed.  
564Users may authenticate using either a public key pair or a conventional (symmetric) key. If public key cryptography is used, public key data is transported in preauthentication data fields to help establish 
565identity. 
566Kerberos uses tickets for authenticating subjects to objects and SESAME uses Privileged Attribute Certificates (PAC), which contain the subject’s identity, access capabilities for the object, access time period, and 
567lifetime of the PAC. The PAC is digitally signed so that the object can validate that it came from the trusted authentication server, which is referred to as the privilege attribute server (PAS). The PAS holds a 
568similar role as the KDC within Kerberos. After a user successfully authenticates to the authentication service (AS), he is presented with a token to give to the PAS. The PAS then creates a PAC for the user to 
569present to the resource he is trying to access. 
570
571
572
573KryptoKnight - is a Peer to Peer authentication protocol incorporated into the NetSP product from IBM.  
574
575
576EAP - framework that supports multiple, optional authentication mechanisms for PPP, including cleartext passwords, challenge-response, and arbitrary dialog sequences. It is intended for use primarily by a 
577host or router that connects to a PPP network server via switched circuits or dial-up lines. It is an authentication framework frequently used in wireless networks and Point-to-Point connections. It is defined in 
578RFC 3748, which made RFC 2284 obsolete, and was updated by RFC 5247. 
579EAP is an authentication framework providing for the transport and usage of keying material and parameters generated by EAP methods.[1] There are many methods defined by RFCs and a number of vendor 
580specific methods and new proposals exist. EAP is not a wire protocol; instead it only defines message formats. Each protocol that uses EAP defines a way to encapsulate EAP messages within that protocol's 
581messages. 
582EAP is in wide use. For example, in IEEE 802.11 (WiFi) the WPA and WPA2 standards have adopted IEEE 802.1X with five EAP types as the official authentication mechanisms. 
583EAP is an authentication framework, not a specific authentication mechanism.[1] It provides some common functions and negotiation of authentication methods called EAP methods. There are currently about 
58440 different methods defined. Methods defined in IETF RFCs include EAP-MD5, EAP-POTP, EAP-GTC, EAP-TLS, EAP-IKEv2, EAP-SIM, EAP-AKA. Additionally a number of vendor-specific methods and new proposals 
585exist. Commonly used modern methods capable of operating in wireless networks include EAP-TLS, EAP-SIM, EAP-AKA, LEAP and EAP-TTLS. Requirements for EAP methods used in wireless LAN authentication 
586are described in RFC 4017. 
587The standard also describes the conditions under which the AAA key management requirements described in RFC 4962 can be satisfied. 
588RFC 2828 (Internet Security Glossary) defines the Extensible Authentication Protocol as a framework that supports multiple, optional authentication mechanisms for PPP, including cleartext passwords, 
589challenge-response, and arbitrary dialog sequences. It is intended for use primarily by a host or router that connects to a PPP network server via switched circuits or dial-up lines. The Remote Authentication 
590Dial-In User Service (RADIUS) is defined as an Internet protocol for carrying dial-in user's authentication information and configuration information between a shared, centralized authentication server and a 
591network access server that needs to authenticate the users of its network access ports. The other option is a distracter. 
592
593
594
595
596
597
598
599
600
601
602
603
604SAML - is an XML-based open standard data format for exchanging authentication and authorization data between parties, in particular, between an identity provider and a service provider. SAML is a product of the OASIS Security 
605Services Technical Committee. SAML dates from 2001; the most recent update of SAML is from 2005. 
606The single most important problem that SAML addresses is the web browser single sign-on (SSO) problem. Single sign-on solutions are abundant at the intranet level (using cookies, for example) but extending these solutions beyond the 
607intranet has been problematic and has led to the proliferation of non-interoperable proprietary technologies. (Another more recent approach to addressing the browser SSO problem is the OpenID protocol.) 
608The SAML specification defines three roles: the principal (typically a user), the identity provider (aka IdP), and the service provider (aka SP). In the use case addressed by SAML, the principal requests a service from the service provider. 
609The service provider requests and obtains an identity assertion from the identity provider. On the basis of this assertion, the service provider can make an access control decision - in other words it can decide whether to perform some 
610service for the connected principal. 
611Before delivering the identity assertion to the SP, the IdP may request some information from the principal - such as a user name and password - in order to authenticate the principal. SAML specifies the assertions between the three 
612parties: in particular, the messages that assert identity that are passed from the IdP to the SP. In SAML, one identity provider may provide SAML assertions to many service providers. Conversely, one SP may rely on and trust assertions 
613from many independent IdPs. 
614SAML does not specify the method of authentication at the identity provider; it may use a username/password, multifactor authentication, etc. A directory service, which allows users to login with a user name and password, is a typical 
615source of authentication tokens (i.e., passwords) at an identity provider. Any of the popular common internet social services also provide identity services that in theory could be used to support SAML exchanges. 
616
617
618XACML - (extensible access control markup language) is a standard for attribute-based access control. XACML 3.0.  The standard defines a declarative access control policy language implemented in XML and a processing model 
619describing how to evaluate authorization requests according to the rules defined in policies. 
620As a published standard specification, one of the goals of XACML is to promote common terminology and interoperability between authorization implementations by multiple vendors. XACML is primarily an Attribute Based Access 
621Control system (ABAC), where attributes (bits of data) associated with a user or action or resource are inputs into the decision of whether a given user may access a given resource in a particular way. Role-based access control (RBAC) can 
622also be implemented in XACML as a specialization of ABAC. 
623The XACML model supports and encourages the separation of the authorization decision from the point of use. When authorization decisions are baked into client applications (or based on local machine userids and Access Control Lists 
624(ACLs)), it is very difficult to update the decision criteria when the governing policy changes. When the client is decoupled from the authorization decision, authorization policies can be updated on the fly and affect all clients immediately. 
625XACML is structured into 3 levels of elements: 
626PolicySet, 
627Policy, and 
628Rule. 
629Both Rules and Requests use Subjects, Resources and Actions. 
630A Subject element is the entity requesting access. A Subject has one or more Attributes. 
631The Resource element is a data, service or system component. A Resource has a single Attribute. 
632An Action element defines the type of access requested on the Resource. Actions have one or more Attributes. 
633An Environment element can optionally provide additional information. 
634
635
636LDAP (x.500) 
637Bind - When an LDAP session is created, that is, when an LDAP client connects to the server, the authentication state of the session is set to anonymous. The BIND operation establishes the authentication state for a session. 
638Simple BIND and SASL PLAIN can send the user's DN and password in plaintext, so the connections utilizing either Simple or SASL PLAIN should be encrypted using Transport Layer Security (TLS). The server typically checks the password 
639against the userPassword attribute in the named entry. Anonymous BIND (with empty DN and password) resets the connection to anonymous state. 
640SASL (Simple Authentication and Security Layer) BIND provides authentication services through a wide range of mechanisms, e.g. Kerberos or the client certificate sent with TLS.[8] 
641BIND also sets the LDAP protocol version. The version is an integer and at present <when?> must be either 2 (two) or 3 (three), although the standard supports integers between 1 and 127 (inclusive) in the protocol. If the client requests a 
642version that the server does not support, the server must set the result code in the BIND response to the code for a protocol error. Normally clients should use LDAPv3, which is the default in the protocol but not always in LDAP libraries. 
643BIND had to be the first operation in a session in LDAPv2, but is not required in LDAPv3 (the current LDAP version). In LDAPv3, each successful BIND request changes the authentication state of the session and each unsuccessful BIND 
644request resets the authentication state of the session. 
645
646
647OpenID - open standard that allows users to be authenticated by certain co-operating sites (known as Relying Parties or RP) using a third party service, eliminating the need for webmasters to provide their own ad hoc systems and 
648allowing users to consolidate their digital identities.[1] 
649
650
651
652
653
654
655
656
657
658Users may create accounts with their preferred OpenID identity providers, and then use those accounts as the basis for signing on to any website which accepts OpenID authentication. The OpenID standard provides a framework for the 
659communication that must take place between the identity provider and the OpenID acceptor (the "relying party").[2] An extension to the standard (the OpenID Attribute Exchange) facilitates the transfer of user attributes, such as name 
660and gender, from the OpenID identity provider to the relying party (each relying party may request a different set of attributes, depending on its requirements).[3] 
661The OpenID protocol does not rely on a central authority to authenticate a user's identity. Moreover, neither services nor the OpenID standard may mandate a specific means by which to authenticate users, allowing for approaches 
662ranging from the common (such as passwords) to the novel (such as smart cards or biometrics). 
663The term OpenID may also refer to an identifier as specified in the OpenID standard; these identifiers take the form of a unique URI, and are managed by some 'OpenID provider' that handles authentication.[1] 
664
665
666CHAP 
667A protocol that uses a three way hanbdshake The server sends the client a challenge which includes a random value(a nonce) to thwart replay attacks. The client responds with the MD5 hash of the nonce and the password.  
668CHAP authenticates a user or network host to an authenticating entity. That entity may be, for example, an Internet service provider. CHAP is specified in RFC 1994. 
669CHAP provides protection against replay attacks by the peer through the use of an incrementally changing identifier and of a variable challenge-value. CHAP requires that both the client and server know the plaintext of the secret, 
670although it is never sent over the network. The MS-CHAP variant does not require either peer to know the plaintext, but has been broken.[1] Thus, CHAP provides better security as compared to Password Authentication Protocol (PAP). 
671
672
673CHAP is an authentication scheme used by Point to Point Protocol (PPP) servers to validate the identity of remote clients. CHAP periodically verifies the identity of the client by using a three-way handshake. This happens at the time of 
674establishing the initial link (LCP), and may happen again at any time afterwards. The verification is based on a shared secret (such as the client user's password).[2] 
675After the completion of the link establishment phase, the authenticator sends a "challenge" message to the peer. 
676The peer responds with a value calculated using a one-way hash function on the challenge and the secret combined. 
677The authenticator checks the response against its own calculation of the expected hash value. If the values match, the authenticator acknowledges the authentication; otherwise it should terminate the connection. 
678At random intervals the authenticator sends a new challenge to the peer and repeats steps 1 through 3. 
679
680
681Diameter 
682
683Diameter is a protocol that has been developed to build upon the functionality of RADIUS and overcome many of its limitations. The creator of this protocol decided to call it Diameter as a play on the term 
684RADIUS, as in the diameter is twice the radius. 
685Diameter is another AAA protocol that provides the same type of functionality as RADIUS and TACACS+ but also provides more flexibility and capabilities to meet the new demands of today’s complex and 
686diverse networks where we want our wireless devices and smart phones to be able to authenticate themselves to our networks and we use roaming protocols, Mobile IP, PPPoE and etc. 
687Diameter provides a base protocol, which defines header formats, security options, commands, and AVPs (Attribute Value Pairs). This base protocol allows for extensions to tie in other services, such as VoIP, 
688FoIP, Mobile IP, wireless, and cell phone authentication. So Diameter can be used as an AAA protocol for all of these different uses. 
689RADIUS and TACACS+ are client/server protocols, which mean that the server portion cannot send unsolicited commands to the client portion. The server portion can only speak when spoken to. Diameter is a 
690peer-based protocol that allows either end to initiate communication. 
691This functionality allows the Diameter server to send a message to the access server to request the user to provide another authentication credential if she is attempting to access a secure resource. 
692This functionality also allows the Diameter server to disconnect the user if necessary for one reason or another. 
693Diameter is backward compatible with RADIUS, uses UDP and AVPs, and provides proxy server support. 
694It has better error detection and correction functionality and failover properties than RADIUS, thus provides better network resilience. 
695Diameter also provides end-to-end security through the use of IPSec or TLS, which is not available in RADIUS. 
696Diameter has the functionality and ability to provide the AAA functionality for other protocols and services because it has a large AVP set. RADIUS has 28 (256) AVPs and Diameter has 232. So, more AVPs allow 
697for more functionality and services to exist and communicate between systems. 
698Diameter provides the following AAA function 
699Authentication 
700PAP, CHAP, EAP 
701End-to-end protection of authentication information 
702Replay attack protection 
703Authorization 
704
705
706
707
708
709
710
711
712
713Redirects, secure proxies, relays, and brokers 
714State reconciliation 
715Unsolicited disconnect 
716Reauthorization on demand 
717Accounting 
718Reporting, ROAMOPS accounting, event monitoring 
719
720
721
722OAuth 
723
724is an open standard for authorization. OAuth provides a method for clients to access server resources on behalf of a resource owner (such as a different client or an end-user). It also provides a process for end-users to authorize third- 
725party access to their server resources without sharing their credentials (typically, a username and password pair), using user-agent redirections. 
726OAuth is a service that is complementary to, and therefore distinct from, OpenID. OAuth is also distinct from OATH, which is a reference architecture for authentication (i.e. not a standard). 
727
728
729
730OpenID vs. pseudo-authentication using OAuth 
731
732The following diagrams highlight the differences between using OpenID and OAuth for authentication. With OpenID, the process starts with the application asking the user for their identity (basically a log-in request by the application, to 
733which the user typically provides an OpenID URI rather than actual credentials). In the case of OAuth, the application specifically requests a limited access OAuth Token (valet key) to access the APIs (enter the house) on the user's behalf 
734(which typically explicitly names the particular rights requested, and does not require the user to enter credentials at all). If the user can grant that access, the application can retrieve the unique identifier for establishing the profile 
735(identity) using the APIs. In either case, the access to the Identity Provider will involve authentication to the Identity Provider, unless some session is already in effect. The result in the OpenID case is that the application allows the user 
736access, because it trusts the OpenID Identity provider. The result in the OAuth case is that the API provider allows the application access because it trusts its own valet keys. 
737
738
739
740SINGLE SIGN ON: 
741
742The advantages of SSO include having the ability to use stronger passwords, easier administration as far as changing or deleting the passwords, minimize the risks of orphan accounts, and requiring less time to 
743access resources. 
744
745
746SSO can be implemented by using scripts that replay the users multiple log-ins, or by using authentication servers to verify a user's identity and encrypted authentication tickets to permit access to system 
747services. 
748Single Sign on was the best answer in this case because it would include Kerberos. 
749
750
751Benefits of using single sign-on include: 
752Reducing password fatigue from different user name and password combinations 
753Reducing time spent re-entering passwords for the same identity 
754Reducing IT costs due to lower number of IT help desk calls about passwords 
755SSO shares centralized authentication servers that all other applications and systems use for authentication purposes and combines this with techniques to ensure that users do not have to actively enter their 
756credentials more than once. 
757SSO users do not need to remember so many passwords to log in to different systems or applications. 
758
759
760Drawbacks: 
761The term enterprise reduced sign-on is preferred by some authors[who?] who believe single sign-on to be impossible in real use cases. 
762
763
764
765
766
767
768
769
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771
772
773As single sign-on provides access to many resources once the user is initially authenticated ("keys to the castle") it increases the negative impact in case the credentials are available to other persons and 
774misused. Therefore, single sign-on requires an increased focus on the protection of the user credentials, and should ideally be combined with strong authentication methods like smart cards and one-time 
775password tokens. 
776Single sign-on also makes the authentication systems highly critical; a loss of their availability can result in denial of access to all systems unified under the SSO. SSO can thus be undesirable for systems to which 
777access must be guaranteed at all times, such as security or plant-floor systems 
778
779OTHERS: 
780
781
782SmartCards - Tamper-resistant microprocessors are used to store and process private or sensitive information, such as private keys or electronic money credit. To prevent an attacker from retrieving or 
783modifying the information, the chips are designed so that the information is not accessible through external means and can be accessed only by the embedded software, which should contain the appropriate 
784security measures. 
785The main difference between memory cards and smart cards is their capacity to process information. A memory card holds information but cannot process information. A smart card holds information and has 
786the necessary hardware and software to actually process that information. 
787A memory card holds a user’s authentication information, so that this user needs only type in a user ID or PIN and presents the memory card to the system. If the entered information and the stored 
788information match and are approved by an authentication service, the user is successfully authenticated.  
789A common example of a memory card is a swipe card used to provide entry to a building. The user enters a PIN and swipes the memory card through a card reader. If this is the correct combination, the reader 
790flashes green and the individual can open the door and enter the building.  
791Memory cards can also be used with computers, but they require a reader to process the information. The reader adds cost to the process, especially when one is needed for every computer. Additionally, the 
792overhead of PIN and card generation adds additional overhead and complexity to the whole authentication process. However, a memory card provides a more secure authentication method than using only a 
793password because the attacker would need to obtain the card and know the correct PIN.  
794Administrators and management need to weigh the costs and benefits of a memory card implementation as well as the security needs of the organization to determine if it is the right authentication mechanism 
795for their environment. 
796One of the most prevalent weaknesses of memory cards is that data stored on the card are not protected. Unencrypted data on the card (or stored on the magnetic strip) can be extracted or copied. Unlike a 
797smart card, where security controls and logic are embedded in the integrated circuit, memory cards do not employ an inherent mechanism to protect the data from exposure. 
798
799
800Hybrid Card  
801A hybrid card has two chips, one with a contact interface and one with a contactless interface. The two chips are not interconnected.  
802
803
804Dual-Interface card  
805Do not confuse this card with the Hybrid Card.  This one has only one chip.  A dual-interface card has a single chip with both contact and contactless interfaces. With dual-interface cards, it is possible to access 
806the same chip using either a contact or contactless interface with a very high level of security. 
807
808
809Inner working of the cards  
810The chips used in all of these cards fall into two categories as well: microcontroller chips and memory chips. A memory chip is like a small floppy disk with optional security. Memory chips are less expensive than 
811microcontrollers but with a corresponding decrease in data management security. Cards that use memory chips depend on the security of the card reader for processing and are ideal for situations that require 
812low or medium security. 
813A microcontroller chip can add, delete, and otherwise manipulate information in its memory. A microcontroller is like a miniature computer, with an input/output port, operating system, and hard disk. Smart 
814cards with an embedded microcontroller have the unique ability to store large amounts of data, carry out their own on-card functions (e.g., encryption and digital signatures) and interact intelligently with a 
815smart card reader. 
816
817
818The selection of a particular card technology is driven by a variety of issues, including: 
819
820
821
822
823
824
825
826
827Application dynamics 
828Prevailing market infrastructure 
829Economics of the business model 
830Strategy for shared application cards 
831
832
833Smart cards are used in many applications worldwide, including: 
834Secure identity applications - employee ID badges, citizen ID documents, electronic passports, driver’s licenses, online authentication devices 
835Healthcare applications - citizen health ID cards, physician ID cards, portable medical records cards 
836Payment applications - contact and contactless credit/debit cards, transit payment cards 
837Telecommunications applications - GSM Subscriber Identity Modules, pay telephone payment cards 
838
839
840
841Detective/administrative - Additional detective/administrative controls are job rotation, the sharing of responsibilities, and reviews of audit records. 
842
843
844
845TECHNICAL CONTROLS 
846Technical security involves the use of safeguards incorporated in computer hardware, operations or applications software, communications hardware and software, and related devices. Technical controls are 
847sometimes referred to as logical controls. 
848Preventive Technical Controls 
849Preventive technical controls are used to prevent unauthorized personnel or programs from gaining remote access to computing resources. Examples of these controls include: 
850•  Access control software.  
851•  Antivirus software.  
852•  Library control systems.  
853•  Passwords.  
854•  Smart cards.  
855•  Encryption.  
856•  Dial-up access control and callback systems. 
857
858
859Preventive Physical Controls 
860Preventive physical controls are employed to prevent unauthorized personnel from entering computing facilities (i.e., locations housing computing resources, supporting utilities, computer hard copy, and input 
861data media) and to help protect against natural disasters. Examples of these controls include: 
862•  Backup files and documentation.  
863•  Fences.  
864•  Security guards.  
865•  Badge systems.  
866•  Double door systems.  
867•  Locks and keys.  
868•  Backup power.  
869•  Biometric access controls.  
870•  Site selection.  
871•  Fire extinguishers.  
872
873
874
875
876Preventive Administrative Controls 
877Preventive administrative controls are personnel-oriented techniques for controlling people’s behavior to ensure the confidentiality, integrity, and availability of computing data and programs. Examples of 
878preventive administrative controls include: 
879•  Security awareness and technical training.  
880•  Separation of duties.  
881•  Procedures for recruiting and terminating employees.  
882•  Security policies and procedures.  
883•  Supervision.  
884•  Disaster recovery, contingency, and emergency plans.  
885•  User registration for computer access. 
886
887
888Security awareness is a preventive measure, not a compensating measure for access violations. 
889
890
891Preventive controls are concerned with avoiding occurrences of risks while deterrent controls are concerned with discouraging violations. Detecting controls identify occurrences and compensating 
892controls are alternative controls, used to compensate weaknesses in other controls. Supervision is an example of compensating control. 
893
894
895
896Access control lists are object-based whereas capability tables are subject-based. 
897Capability tables are used to track, manage and apply controls based on the object and rights, or capabilities of a subject.  For example, a table identifies the object, specifies access rights allowed for a subject, 
898and permits access based on the user's posession of a capability (or ticket) for the object. It is a row within the matrix. 
899To put it another way, A capabiltiy table is different from an ACL because the subject is bound to the capability table, whereas the object is bound to the ACL. 
900
901
902It [ACL] specifies a list of users [subjects] who are allowed access to each object" CBK, p. 188 
903A capability table is incorrect. "Capability tables are used to track, manage and apply controls based on the object and rights, or capabilities of a subject. For example, a table identifies the object, specifies access 
904rights allowed for a subject, and permits access based on the user's posession of a capability (or ticket) for the object." CBK, pp. 191-192. The distinction that makes this an incorrect choice is that access is based 
905on posession of a capability by the subject. 
906To put it another way. "A capabiltiy table is different from an ACL because the subject is bound to the capability table, whereas the object is bound to the ACL." 
907An access control matrix is incorrect.  
908The access control matrix is a way of describing the rules for an access control strategy. The matrix lists the users, groups and roles down the left side and the resources and functions across the top. 
909The cells of the matrix can either indicate that access is allowed or indicate the type of access. Harris describes it as a table if subjects and objects specifying the access rights a certain subject possesses 
910pertaining to specific objects. 
911In either case, the matrix is a way of analyzing the access control needed by a population of subjects to a population of objects. This access control can be applied using rules, ACL's, capability tables, etc. 
912Access Matrix Model 
913An access control matrix is a table of subjects and objects indicating what actions individual subjects can take upon individual objects. Matrices are data structures that programmers implement as table lookups 
914that will be used and enforced by the operating system.  
915This type of access control is usually an attribute of DAC models. The access rights can be assigned directly to the subjects (capabilities) or to the objects (ACLs). 
916
917
918Honeypots - The primary purpose of a honeypot is to study the attack methods of an attacker for the purposes of understanding their methods and improving defenses. 
919
920
921
922
923
924Environmental error, the environment in which a system is installed somehow causes the system to be vulnerable. This may be due, for example, to an unexpected interaction between an application and the 
925operating system or between two applications on the same host. A configuration error occurs when user controllable settings in a system are set such that the system is vulnerable. In an access validation error, 
926the system is vulnerable because the access control mechanism is faulty. In an exceptional condition handling error, the system somehow becomes vulnerable due to an exceptional condition that has arisen. 
927
928
929A network-based vulnerability assessment system either re-enacts system attacks, noting and recording responses to the attacks, or probes different targets to infer weaknesses from their responses. Since 
930they are actively attacking or scanning targeted systems, network-based vulnerability assessment systems are also called active vulnerability systems. Credential-based and passive are related to host-based 
931vulnerability assessment systems. 
932
933
934Cognitive passwords are fact or opinion-based information used to verify an individual's identity. Passwords that can be used only once are one-time or dynamic passwords. Password generators that use a 
935challenge response scheme refer to token devices.  
936A passphrase is a sequence of characters that is longer than a password and is transformed into a virtual password. 
937
938
939
940Reporting structure for the Information Systems Security function - Operations would rank lowest of the available answers as they are more apt to be management so would be considered least effective 
941structure for the Information Systems Security function. 
942In order to offer more independence and get more attention from management, an IT/IS security function should be independent from IT/IS operations and ideally report directly to the CEO. If it were to report 
943to IT/IS, operations is probably the last function the IS Security function should be reporting to.  
944
945
946DB VIEW 
947A number of operations can be performed in a relational algebra to build relations and operate on the data. Five operations are primitives (Select, Project, Union, Difference and Product) and the other 
948operations can be defined in terms of those five.   A View is defined from the operations of Join, Project, and Select 
949External consistency ensures that the data stored in the database is consistent with the real world. 
950
951
952INSIDE ATTACK - An inside attack is an attack initiated by an entity inside the security perimeter, an entity that is authorized to access system resources but uses them in a way not approved by those who 
953granted the authorization whereas an outside attack is initiated from outside the perimeter, by an unauthorized or illegitimate user of the system. An active attack attempts to alter system resources to affect 
954their operation and a passive attack attempts to learn or make use of the information from the system but does not affect system resources. 
955
956
957PASSWORD TOKENS: 
958Tokens are electronic devices or cards that supply a user's password for them. A token system can be used to supply either a static or a dynamic password. There is a big difference between the static and 
959dynamic systems, a static system will normally log a user in but a dynamic system the user will often have to log themselves in. 
960
961
962Static Password Tokens:  
963The owner identity is authenticated by the token. This is done by the person who issues the token to the owner (normally the employer). The owner of the token is now authenticated by "something you have". 
964The token authenticates the identity of the owner to the information system. An example of this occurring is when an employee swipes his or her smart card over an electronic lock to gain access to a store 
965room.  
966
967
968Synchronous Dynamic Password Tokens:  
969This system is a lot more complex then the static token password. The synchronous dynamic password tokens generate new passwords at certain time intervals that are synched with the main system. The 
970password is generated on a small device similar to a pager or a calculator that can often be attached to the user's key ring. Each password is only valid for a certain time period, typing in the wrong password in 
971the wrong time period will invalidate the authentication. The time factor can also be the systems downfall. If a clock on the system or the password token device becomes out of synch, a user can have troubles 
972authenticating themselves to the system. 
973
974
975
976
977- The token generates a new unique password value at fixed time intervals (this password could be the time of day encrypted with a secret key). 
978- the unique password is entered into a system or workstation along with an owner's PIN. 
979- The authentication entity in a system or workstation knows an owner's secret key and PIN, and the entity verifies that the entered password is valid and that it was entered during the valid time window. 
980Synchronous Tokens:  
981A Synchronous token generates a one-time password that is only valid for a short period of time. Once the password is used it is no longer valid, and it expires if not entered in the acceptable time frame. 
982
983
984
985Asynchronous Dynamic Password Tokens: 
986The clock synching problem is eliminated with asynchronous dynamic password tokens. This system works on the same principal as the synchronous one but it does not have a time frame. A lot of big companies 
987use this system especially for employee's who may work from home on the companies VPN (Virtual private Network).  
988
989
990Challenge Response Tokens:  
991This is an interesting system. A user will be sent special "challenge" strings at either random or timed intervals. The user inputs this challenge string into their token device and the device will respond by 
992generating a challenge response. The user then types this response into the system and if it is correct they are authenticated. 
993
994
995BUSINESS AVAILABILITY PLANNING: 
996The following measures are used to compensate for both internal and external access violations: 
997- Backups 
998- RAID (Redundant Array of Independent Disks) technology 
999- Fault tolerance 
1000- Business Continuity Planning 
1001- Insurance 
1002
1003
1004ASSURANCE PROCEDURES: 
1005Controls provide accountability for individuals accessing information. Assurance procedures ensure that access control mechanisms correctly implement the security policy for the entire life cycle of an 
1006information system. 
1007
1008
1009
1010Information Flow Model combined with Bell Lapadula 
1011Securing the data manipulated by computing systems has been a challenge in the past years. Several methods to limit the information disclosure exist today, such as access control lists, firewalls, and 
1012cryptography. However, although these methods do impose limits on the information that is released by a system, they provide no guarantees about information propagation.  For example, access control lists 
1013of file systems prevent unauthorized file access, but they do not control how the data is used afterwards. Similarly, cryptography provides a means to exchange information privately across a non-secure 
1014channel, but no guarantees about the confidentiality of the data are given once it is decrypted. 
1015In low level information flow analysis, each variable is usually assigned a security level. The basic model comprises two distinct levels: low and high, meaning, respectively, publicly observable information, and 
1016secret information. To ensure confidentiality, flowing information from high to low variables should not be allowed. On the other hand, to ensure integrity, flows to high variables should be restricted. 
1017More generally, the security levels can be viewed as a lattice with information flowing only upwards in the lattice. 
1018
1019
1020Noninterference Models  
1021This could have been another good answer as it would help in minimizing the damage from covert channels.   
1022The goal of a noninterference model is to help ensure that high-level actions (inputs) do not determine what low-level user s can see (outputs ) . Most of the security models presented are secured by permitting 
1023restricted flows between high- and low-level users. The noninterference model maintains activities at different security levels to separate these levels from each other. In this way, it minimizes leakages that may 
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033happen through covert channels, because there is complete separation (noninterference) between security levels. Because a user at a higher security level has no way to interfere with the activities at a lower 
1034level, the lower-level user cannot get any information from the higher leve.  
1035
1036
1037TAKE-GRANT SYSTEM models a protection system which consists of a set of states and state transitions. A directed graph shows the connections between the nodes of this system. These nodes are representative of the subjects or 
1038objects of the model. The directed edges between the nodes represent the rights that one node has over the linked node. 
1039
1040
1041
1042Port knocking - is where the client will attempt to connect to a predefined set of ports to identify him as an authorized client. The port knocking sequence is used to identify the client as a legitimate user.  
1043
1044
1045Cryptcat - Twofish encryption to encrypt network traffic thereby evading IDS/IDP detection.  
1046Netcat is a utility that can be used to open ports on a compromised host.  
1047Cryptcat does this but supports twofish (Schneier) encryption which is not decryptable by an IDS in transit.   
1048
1049
1050IDS/IPS 
1051Intrusion Detection attempts to identify and isolate computer and network attacks by observing network logs or other audit data.  
1052Audit trails maintain a record of system activity both by system and application processes and by user activity of systems and applications. In conjunction with appropriate tools and procedures, audit trails can 
1053assist in detecting security violations, performance problems, and flaws in applications. 
1054Intrusion detection refers to the process of identifying attempts to penetrate a system and gain unauthorized access. If audit trails have been designed and implemented to record appropriate information, they 
1055can assist in intrusion detection. Although normally thought of as a real-time effort, intrusions can be detected in real time, by examining audit records as they are created (or through the use of other kinds of 
1056warning flags/notices), or after the fact (e.g., by examining audit records in a batch process). 
1057Real-time intrusion detection is primarily aimed at outsiders attempting to gain unauthorized access to the system. It may also be used to detect changes in the system's performance indicative of, for example, a 
1058virus or worm attack (forms of malicious code). There may be difficulties in implementing real-time auditing, including unacceptable system performance. 
1059After-the-fact identification may indicate that unauthorized access was attempted (or was successful). Attention can then be given to damage assessment or reviewing controls that were attacked. 
1060Statistical Anomaly-Based IDS - With this method, an IDS acquires data and defines a "normal" usage profile for the network or host that is being monitored. Some disadvantages of a statistical anomaly-based 
1061ID are that it will not detect an attack that does not significantly change the system operating characteristics, or it may falsely detect a non-attack event that had caused a momentary anomaly in the system. 
1062A network-based IDS is passive while it acquires data. 
1063
1064
1065
1066Wardialling countermeasure - Knowledge of modem numbers is a poor access control method as an attacker can discover modem numbers by dialing all numbers in a range. Requiring user authentication before remote access is granted will help in avoiding 
1067unauthorized access over a modem line. 
1068
1069
1070LOGO BANNERS (external users) VS WRITTEN AGREEMENT (internal users) 
1071There are two possible answers based on how the question is presented, this question could either apply to internal users or ANY anonymous/external users.  
1072Internal users should always have a written agreement first, then logon banners serve as a constant reminder. 
1073
1074
1075Banners at the log-on time should be used to notify external users of any monitoring that is being conducted.  A good banner will give you a better legal stand and also makes it obvious the user was warned 
1076about who should access the system, who is authorized and unauthorized,  and if it is an unauthorized user then he is fully aware of trespassing.   Anonymous/External users, such as those logging into a web 
1077site, ftp server or even a mail server; their only notification system is the use of a logon banner. 
1078
1079
1080Incident handling: 
1081Analysis and tracking. In this step, your main objective is to examine and analyze what has occurred and focus on determining the root cause of the incident. 
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091Recovery is incorrect as recovery is about resuming operations or bringing affected systems back into production  
1092Containment is incorrect as containment is about reducing the potential impact of an incident.  
1093Triage is incorrect as triage is about determining the seriousness of the incident and filtering out false positives 
1094
1095
1096
1097Access Control Objectives: 
1098Availability assures that a system's authorized users have timely and uninterrupted access to the information in the system. The additional access control objectives are reliability and utility. These and 
1099other related objectives flow from the organizational security policy. This policy is a high-level statement of management intent regarding the control of access to information and the personnel who are 
1100authorized to receive that information. Three things that must be considered for the planning and implementation of access control mechanisms are the threats to the system, the system's vulnerability to these 
1101threats, and the risk that the threat may materialize 
1102
1103
1104Batch and Scripts 
1105Because scripts contain credentials, they must be stored in a protected area and the transmission of the scripts must be dealt with carefully. Operators might need access to batch files and scripts. The least 
1106privilege concept requires that each subject in a system be granted the most restrictive set of privileges needed for the performance of authorized tasks. The need-to-know principle requires a user having 
1107necessity for access to, knowledge of, or possession of specific information required to perform official tasks or services. 
1108
1109
1110
1111Constrained user interfaces limit the functions that can be selected by a user. 
1112
1113
1114Emanation attacks are the act of intercepting electrical signals that radiate from computing equipment. There are several countermeasures including shielding cabling, white noise, control zones, and 
1115TEMPEST equipment (this is a Faraday cage around the equipment) 
1116
1117
1118
1119LC and MAC; IEEE 802.2 and 802.3  
1120The data link layer, or Layer 2, of the OSI model is responsible for adding a header and a trailer to a packet to prepare the packet for the local area network or wide area network technology binary format for 
1121proper line transmission.  
1122Layer 2 is divided into two functional sublayers.  
1123The upper sublayer is the Logical Link Control (LLC) and is defined in the IEEE 802.2 specification. It communicates with the network layer, which is immediately above the data link layer.  
1124Below the LLC is the Media Access Control (MAC) sublayer, which specifies the interface with the protocol requirements of the physical layer.  
1125Thus, the specification for this layer depends on the technology of the physical layer.  
1126The IEEE MAC specification for Ethernet is 802.3, Token Ring is 802.5, wireless LAN is 802.11, and so on. When you see a reference to an IEEE standard, such as 802.11 or 802.16, it refers to the protocol working 
1127at the MAC sublayer of the data link layer of the protocol stack. 
1128
1129
1130
11312.A. Determine Communication architecture 
11322.A. 1Unified communications (e.g. convergence, collaboration, messaging) 
11332.A.2 Content type (e.g. data, voice, video, facsimile) 
11342.A.3 Transport mechanisms (e.g. satellite, landlines, microwave, radio, fiber) 
1135Token Ring was designed to be a more fault-tolerant topology than Ethernet, and can be a very resilient topology when properly implemented. 
1136ARCnet is a LAN media access method, not a topology. It uses token-passing (LAN transmission protocol) in a star topology on a coaxial cable. 
1137In a BUS TOPOLOGY, all the transmissions of the network travel the full length of cable and are received by all other stations. This topology is associated with Ethernet LAN 
1138media access. In a ring topology, all nodes are connected by unidirectional transmission links to form a closed loop. In a star technology, all stations are directly connected 
1139to a central device. FDDI is not a LAN topology, but a LAN media access method. 
1140
1141
1142Start and stop bits mark the beginning and the end of each transfer in asynchronous communication. 
1143
1144
1145With Cyclic Redundancy Check (CRC) or Frame Check Sequence (FCS), a single set of check digits is generated for each frame transmitted, based on the contents of the 
1146frame, and appended to the tail of the frame. It is used for situations where bursts of errors may be present (parity and block sum checks are not effective at detecting 
1147bursts of errors). Block chaining check is not a common error correction method. 
1148
1149
1150An Ethernet address is a 48-bit address that is hard-wired into the Network Interface Cards (NIC) of the network node. 
1151A Media Access Control address (MAC address) is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses 
1152are used for numerous network technologies and most IEEE 802 network technologies, including Ethernet.  Logically, MAC addresses are used in the Media Access Control 
1153protocol sub-layer of the OSI reference model. 
1154
1155
1156The older coaxial cable has been widely replaced with twisted pair, which is extremely resistant to failure, especially in a star-wired configuration. 
1157
1158
1159Frame relay uses a public switched network to provide Wide Area Network (WAN) connectivity. 
1160
1161
1162Thicknet is a coaxial cable with segments of up to 500 meters, also known as 10Base5. Thinnet is a coaxial cable with segments of up to 185 meters. Unshielded twisted 
1163pair (UTP) has three variations: 10 Mbps (10BaseT), 100 Mbps (100BaseT) or 1 Gbps (1000BaseT). ARCnet is a LAN media access method. 
1164
1165
11662.A.4 Communication topology (e.g. centralized, distributed, cloud, mesh) 
1167The main characteristic of a multi-homed host is that is has multiple network interfaces, each connected to logically and physically separate networks. IP routing should 
1168be disabled to prevent the firewall from routing packets directly from one interface to the other. 
1169
1170
1171
1172
1173
1174Frame relay and X.25 are both examples of packet-switching technologies.  In packet-switched networks there are no dedicated connections between endpoints, and 
1175data is divided into packets and reassembled on the receiving end. 
1176
1177
1178ATM is an example of a fast packet-switching network that can be used for either data, voice or video, but packets are of fixed size. 
1179
1180
1181LAN Transmission Methods  
1182LAN data transmissions fall into three classifications: unicast, multicast, and broadcast.  
1183In each type of transmission, a single packet is sent to one or more nodes.  
1184In a unicast transmission, a single packet is sent from the source to a destination on a network. First, the source node addresses the packet by using the address of the 
1185destination node. The package is then sent onto the network, and finally, the network passes the packet to its destination.  
1186A multicast transmission consists of a single data packet that is copied and sent to a specific subset of nodes on the network. First, the source node addresses the packet by 
1187using a multicast address. The packet is then sent into the network, which makes copies of the packet and sends a copy to each node that is part of the multicast address.  
1188A broadcast transmission consists of a single data packet that is copied and sent to all nodes on the network. In these types of transmissions, the source node addresses 
1189the packet by using the broadcast address. The packet is then sent on to the network, which makes copies of the packet and sends a copy to every node on the network.  
1190
1191
1192LAN Topologies  
1193LAN topologies define the manner in which network devices are organized. Four common LAN topologies exist: bus, ring, star, and tree. These topologies are logical 
1194architectures, but the actual devices need not be physically organized in these configurations. Logical bus and ring topologies, for example, are commonly organized 
1195physically as a star. A bus topology is a linear LAN architecture in which transmissions from network stations propagate the length of the medium and are received by all 
1196other stations. Of the three most widely used LAN implementations, Ethernet/IEEE 802.3 networks—including 100BaseT—implement a bus topology 
1197
1198
1199Synchronous Communication is characterized by very high speed transmission rates that are governed by electronic clock timing signals. 
1200
1201
1202Generally, the methods for multiplexing data include the following : 
1203•   Time-division multiplexing (TDM): information from each data channel is allocated bandwidth based on pre-assigned time slots, regardless of whether there is data to 
1204   transmit. 
1205•   Asynchronous time-division multiplexing (ATDM): information from data channels is allocated bandwidth as needed, via dynamically assigned time slots. 
1206•   Frequency division multiplexing (FDM): information from each data channel is allocated bandwidth based on the signal frequency of the traffic. 
1207•   Statistical multiplexing: Bandwidth is dynamically allocated to any data channels that have information to transmit. 
1208
1209
1210IEEE 802.3 specifies the standard for Ethernet and uses CSMA/CD, not token-passing. 
1211
1212
1213
1214
1215
1216
1217The IEEE 802.5 standard defines the token ring media access method. 802.3 refers to Ethernet's CSMA/CD, 802.11 refers to wireless communications and 802.2 refers to 
1218the logical link control. 
1219
1220
1221Serial Line IP (SLIP) was developed in 1984 to support TCP/IP networking over low-speed serial interfaces. 
1222
1223
1224The Point-to-Point Protocol (PPP) was designed to support multiple network types over the same serial link, just as Ethernet supports multiple network types over the 
1225same LAN. PPP replaces the earlier Serial Line Internet Protocol (SLIP) that only supports IP over a serial link. PPTP is a tunneling protocol. 
1226
1227
1228A network topology defines the manner in which the network devices are organized to facilitate communications. Common LAN technologies are: 
1229bus 
1230ring 
1231star 
1232meshed 
1233
1234
1235LAN transmission methods refer to the way packets are sent on the network and are: 
1236unicast 
1237multicast 
1238broadcast 
1239
1240
1241LAN transmission protocols are the rules for communicating between computers on a LAN. Common LAN transmission protocols are: 
1242CSMA/CD 
1243polling 
1244token-passing 
1245
1246
1247LAN media access methods control the use of a network (physical and data link layers). They can be: 
1248Ethernet 
1249ARCnet 
1250Token ring 
1251FDDI 
1252
1253
1254
1255Very-high data-rate Digital Subscriber Line (VDSL) can deliver up to 52 Mbps downstream over a single copper twisted pair over a relatively short distance (1000 to 4500 
1256feet). DSL (Digital Subscriber Line) is a modem technology for broadband data access over ordinary copper telephone lines (POTS) from homes and businesses. xDSL refers 
1257
1258
1259
1260
1261collectively to all types of DSL, such as ADSL (and G.Lite), HDSL, SDSL, IDSL and VDSL etc. They are sometimes referred to as last-mile (or first mile) technologies because 
1262they are used only for connections from a telephone switching station to a home or office, not between switching stations. 
1263xDSL is similar to ISDN in as much as both operate over existing copper telephone lines (POTS) using sophisticated modulation schemes and both require the short runs to a 
1264central telephone office 
1265
1266
1267Diverse routing—This is the practice of routing traffic through different cable facilities. Organizations can obtain both diverse routing and alternate routing, but the cost is 
1268not cheap. Most of these systems use buried facilities. These systems usually enter a facility through the basement and can sometimes share space with other mechanical 
1269equipment. Recognize that this sharing adds to the risk of potential failure. Also, many cities have aging infrastructures, which is another potential point of failure. 
1270
1271
1272Alternate routing—Redundant routing provides use of another transmission line if the regular line is busy or unavailable. This can include using a dialup connection in place 
1273of a dedicated connection, cell phone instead of a land line, or microwave communication in place of a fiber connection. 
1274Last mile protection—This is a good choice for recovery facilities; it provides a second local loop connection, and is even more redundantly capable if an alternative carrier 
1275is used. 
1276Voice communication recovery—Many organizations are highly dependent on voice communications. Others have started making the switch to Voice over IP (VoIP) for 
1277both voice and fax communication because of the cost savings. Some number of land lines should always be maintained to provide backup capability. 
1278
1279
1280T1 CONNECTIONS 
1281A common way to create fault tolerance with leased lines is to group several T1s together with an inverse multiplexer placed at both ends of the connection.   
1282In fact it would be a Multiplexer at one end and DeMultiplexer at other end or vice versa. Inverse Multiplexer at both end. 
1283In electronics, a multiplexer (or mux) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line.  A multiplexer of 
12842n inputs has n select lines, which are used to select which input line to send to the output. Multiplexers are mainly used to increase the amount of data that can be sent 
1285over the network within a certain amount of time and bandwidth. A multiplexer is also called a data selector. 
1286An electronic multiplexer makes it possible for several signals to share one device or resource, for example one A/D converter or one communication line, instead of having 
1287one device per input signal. 
1288On the other hand, a demultiplexer (or demux) is a device taking a single input signal and selecting one of many data-output-lines, which is connected to the single input. A 
1289multiplexer is often used with a complementary demultiplexer on the receiving end. 
1290An electronic multiplexer can be considered as a multiple-input, single-output switch, and a demultiplexer as a single-input, multiple-output switch 
1291Digital Signal level 1 (DS-1) is the framing specification used for transmitting digital signals at 1.544 Mbps on a T1 facility. DS-0 is the framing specification used in 
1292transmitting digital signals over a single 64 Kbps channel over a T1 facility. DS-3 is the framing specification used for transmitting digital signals at 44.736 Mbps on a T3 
1293facility. DS-2 is not a defined framing specification. 
1294
1295
1296FRAME 
1297Ethernet is frame based network technology. 
1298
1299
1300
1301
1302
1303SEGMENT 
1304A segment is the unit of end-to-end transmission in the TCP protocol. A segment consists of a TCP header followed by application data. A segment is transmitted by 
1305encapsulation inside an IP datagram. 
1306PACKET 
1307A packet is the unit of data passed across the interface between the internet layer and the link layer. It includes an IP header and data. A packet may be a complete IP 
1308datagram or a fragment of an IP datagram. 
1309FRAME 
1310A frame is the unit of transmission in a link layer protocol, and consists of a link-layer header followed by a packet. 
1311
1312
13132.B Determine Network Architecture 
13142.B.1 Network types (e.g. public, private, hybrid) 
13152.B.2 Protocols 
1316
1317
1318IP headers contain 32-bit addresses (in IPv4) and 128 in IPv6. In an Ethernet local area network, however, addresses for attached devices are 48 bits long. The physical 
1319machine address is also known as a Media Access Control (MAC) address. 
1320The Address Resolution Protocol (ARP) is used to match an IP address to an Ethernet address so the packet can be sent to the appropriate node. Reverse Address 
1321Resolution Protocol (RARP) is used to match an Ethernet address to an IP address. 
1322
1323
1324OSI: SET is provided at the application level. The SET(tm) Specification, is an open technical standard for the commerce industry developed by Visa and MasterCard as a 
1325way to facilitate secure payment card transactions over the Internet. Digital Certificates create a trust chain throughout the transaction, verifying cardholder and merchant 
1326validity, a process unparalleled by other Internet security solutions. Software vendors whose products pass SET Compliance Testing are eligible to display the SET Mark on 
1327their products, as are merchants, financial institutions, and promotional sites that utilize or advertise licensed software. 
1328SET was developed by SETco, led by VISA and MasterCard (and involving other companies such as GTE, IBM, Microsoft, Netscape, RSA, Safelayer — formerly SET Projects — 
1329and VeriSign. VeriFone - who built one of the earliest Internet Payment gateways used by several leading banks was also closely involved.) starting in 1996. SET was based 
1330on X.509 certificates with several extensions. The first version was finalised in May 1997 and a pilot test was announced in July 1998. 
1331SET allowed parties to identify themselves to each other and exchange information securely. SET used a cryptographic blinding algorithm that, in effect, would have let 
1332merchants substitute a certificate for a user's credit-card number. If SET were used, the merchant itself would never have had to know the credit-card numbers being sent 
1333from the buyer, which would have provided verified good payment but protected customers and credit companies from fraud. 
1334
1335
1336Connection-oriented protocols provide reliability of the service provided to the higher layer. It is the responsibility of such protocols in the transport layer to enhance the 
1337quality of service provided by the network layer. 
1338
1339
1340Transport Layer Security (TLS) is a two-layered socket layer security protocol that contains: 
1341
1342
1343
1344
1345
1346
1347
1348TLS Record Protocol and the, 
1349Transport Layer Security (TLS) Handshake Protocol. 
1350
1351
1352Secure Sockets Layer (SSL) is the technology used in most Web-based applications. SSL version 2.0 supports strong authentication of the web server, but the authentication 
1353of the client side only comes with version 3.0. SSL v4 is not a defined standard. 
1354The Secure Sockets Layer (SSL) is a commonly-used protocol for managing the security of a message transmission on the Internet.  
1355SSL has recently been succeeded by Transport Layer Security (TLS), which is based on SSL.  
1356According to the cited source, it is operating at the Application/Transport layers. 
1357
1358
1359S-HTTP - An early standard for encrypting HTTP documents, Secure HTTP (S-HTTP) is designed to send individual messages securely. SSL is designed to establish a secure 
1360connection between two computers. SET was originated by VISA and MasterCard as an Internet credit card protocol using digital signatures. Kerberos is an authentication 
1361system. 
1362
1363
1364SQL 
1365The Structured Query Language (SQL), implemented at the session layer (layer 5) of the OSI/ISO model provides users with a way to define their information requirements. 
1366SQL is by definition a language for querying and accessing data in databases, which includes transaction management to keep the database consistent.  It involves setting 
1367up and maintaining sessions (between the host issuing queries and the database server) and it uses the concept of transactions.  
1368Communication between computers is established, maintained and terminated by the session layer.  The session layer is layer 5 of the OSI model.  SQL is an example of a 
1369session layer protocol.  The session layer is in contact with the session layer of the remote machine it is communicating with. 
1370
1371
1372A SOCKS based server operates at the Session layer of the OSI model. 
1373SOCKS is an Internet protocol that allows client-server applications to transparently use the services of a network firewall. SOCKS is an abbreviation for "SOCKetS".  As of 
1374Version 5 of SOCK, both UDP and TCP is supported.  
1375One of the best known circuit-level proxies is SOCKS proxy server.  The basic purpose of the protocol is to enable hosts on  one side of a SOCKS server to gain access to hosts 
1376on the other side of a SOCKS Server, without requiring direct “IP-reachability”The protocol was originally developed by David Koblas, a system administrator of MIPS 
1377Computer Systems. After MIPS was taken over by Silicon Graphics in 1992, Koblas presented a paper on SOCKS at that year's Usenix Security Symposium and SOCKS became 
1378publicly available. The protocol was extended to version 4 by Ying-Da Lee of NEC. SOCKS includes two components, the SOCKS server and the SOCKS client. 
1379
1380
1381Remote Procedure Call (RPC, UDP port 111) is a protocol that allows two computers to coordinate in executing software. RPC can be used by a program on one 
1382computer to transfer execution of a subroutine to another computer, and have the results returned to the first. RPC is a fragile service, and most operating systems cannot 
1383handle arbitrary data being sent to an RPC port. It is best used in trusted LAN environments and should not usually be allowed through the organization's firewall. RPC is 
1384being replaced by Secure-RPC. 
1385
1386
1387
1388
1389
1390
1391
1392
1393Session layer, which establishes, maintains and manages sessions and synchronization of data flow.  Session layer protocols control application-to-application 
1394communications, which is what an RPC call is. 
1395Secure RPC provides authentication services. 
1396Secure RPC is an authentication method that authenticates both the host and the user who is making a request for a service. Secure RPC uses the Diffie-Hellman 
1397authentication mechanism. This authentication mechanism uses DES encryption. Applications that use Secure RPC include NFS and the NIS+ name service. 
1398
1399
1400TFTP (Trivial File Transfer Protocol) is sometimes used to transfer configuration files from equipments such as routers but the primary difference between FTP and TFTP is 
1401that TFTP does not require authentication. Speed and ability to automate are not important. 
1402Both of these protocols (FTP and TFTP) can be used for transferring files across the Internet. The differences between the two protocols are explained below: 
1403FTP is a complete, session-oriented, general purpose file transfer protocol. TFTP is used as a bare-bones special purpose file transfer protocol. 
1404
1405
1406Secure shell (SSH) was designed as an alternative to the above insecure protocols and allows users to securely access resources on remote computers over an encrypted 
1407tunnel.  The Secure Shell Protocol (SSH) is a protocol for secure remote login and other secure network services over an insecure network.  The SSH authentication protocol 
1408runs on top of the SSH transport layer protocol and provides a single authenticated tunnel for the SSH connection protocol. 
1409
1410
1411SSH’s services include remote log-on, file transfer, and command execution. It also supports port forwarding, which redirects other protocols through an encrypted SSH 
1412tunnel. Many users protect less secure traffic of protocols, such as X Windows and VNC (virtual network computing), by forwarding them through a SSH tunnel. 
1413
1414
1415The Transport layer sets up communication between computer systems, while the Session layer sets up connections between applications. 
1416TCP is the only one of the mentioned protocols to operate at the transport layer (layer 4). 
1417
1418
1419The Internet layer in the TCP/IP protocol stack corresponds to the network layer (layer 3) in the OSI/ISO model. The host-to-host layer corresponds to the transport layer 
1420(layer 4) in the OSI/ISO model. The Network access layer corresponds to the data link and physical layers (layers 2 and 1) in the OSI/ISO model. The session layer is not 
1421defined in the TCP/IP protocol stack. 
1422In the TCP/IP protocol model, the Internet layer defines the IP datagram and handles the routing of data across networks. 
1423
1424
1425The OSI/ISO Data Link layer is made up of two sub-layers; (1) the Media Access Control layer refers downward to lower layer hardware functions and (2) the Logical Link 
1426Control refers upward to higher layer software functions. Other choices are distracters. 
1427
1428
1429Port 119 is normally used for the Network News Transfer Protocol. It is thus not need for a mail server, which would normally listen to ports 25 (SMTP), 110 (POP3) and 143 
1430(IMAP). 
1431
1432
1433Network address translation (NAT) is concerned with IP address translation between two networks and operates at the network layer (layer 3). 
1434
1435
1436
1437
1438
1439
1440
1441
1442With dynamic translation (also called Automatic, Hide Mode, or IP Masquerade), a large group of internal clients to share a single or small group of ROUTABLE IP addresses 
1443for the purpose of hiding their identities when communicating with external hosts or expanding the internal network address space.  
1444Static translation (also called port forwarding), assigns a fixed address to a specific internal network resource (usually a server). Static NAT is required to make internal 
1445hosts available for connection from external hosts.  
1446With static translation (also called port forwarding), a specific internal network resource (usually a server) has a fixed translation that never changes. Static NAT is required 
1447to make internal hosts available for connection from external hosts. In dynamic translation (also called Automatic, Hide Mode, or IP Masquerade), a large group of internal 
1448clients share a single or small group of internal IP addresses for the purpose of hiding their identities or expanding the internal network address space. Load Balancing 
1449Translation is used to translate a single IP address and port to a pool of identically configured servers so that a single public address can be served by a number of servers. In 
1450Network Redundancy Translation, multiple Internet connections are attached to a single NAT firewall that it chooses and uses based on load and availability. 
1451Load Balancing Translation is used to translate a single IP address and port to a pool of identically configured servers so that a single public address can be served by a 
1452number of servers. In Network Redundancy Translation, multiple Internet connections are attached to a single NAT firewall that it chooses and uses based on load and 
1453availability. 
1454
1455
1456X.400 is used in e-mail as a message handling protocol. X.500 is used in directory services. X.509 is used in digital certificates and X.800 is used a network security 
1457standard. 
1458
1459
14602.B.3 Securing common services (e.g. wireless, e-mail, VoIP) 
1461
1462
1463VOIP: 
1464H323 Protocol 
1465SIP 
1466SS7 
1467
1468
1469PCM 
1470Jitter 
1471End to End Delay 
1472
1473
1474
1475Wireless: 
1476WEP, WPA, WPA2 
1477
1478802.1x 
1479
1480
1481
1482
1483
1484
1485
1486
1487
14882.C Protect Communications and Networks 
14892.C.1 Communications and network policies 
14902.C.2 Boundary protection (e.g. firewalls, VPNs, airgaps) 
1491L2TP and PPTP were both designed for individual client to server connections; they enable only a single point-to-point connection per session. Dial-up VPNs use L2TP often. 
1492Both L2TP and PPTP operate at the data link layer (layer 2) of the OSI model. PPTP uses native PPP authentication and encryption services and L2TP is a combination of PPTP 
1493and Layer 2 Forwarding protocol (L2F). 
1494PPTP operates at the data link layer (layer 2) of the OSI model and uses native PPP authentication and encryption services. Designed for individual client to server 
1495connections, it enables only a single point-to-point connection per session.  
1496PPTP - Point-to-Point Tunneling Protocol - extends the Point to Point Protocol (PPP) standard for traditional dial-up networking.  PPTP is best suited for the remote access 
1497applications of VPNs, but it also supports LAN internetworking.  
1498PPTP operates at Layer 2 of the OSI model. 
1499
1500
1501
1502STATEFUL / SESSIONS - The question is explict in asking *easily*. With a TCP packet there is a distinct state or sequence that can be expected.  Consult the references for 
1503further details. 
1504ICMP, IP and UDP don't have any concept of a session; i.e. each packet or datagram is handled individually, with no reference to the contents of the previous one. With no 
1505sessions, these protocols usually cannot be filtered on the state of the session. Some newer firewalls, however, simulate the concept of state for these protocols, and filter 
1506out unexpected packets based upon normal usage. Although these are commonly treated like normal stateful filters, they are more complex to program, and hence more 
1507prone to errors. 
1508A stateful packet filter or stateful inspection inspects each packet and only allows known connection states through. So, if a SYN/ACK packet was recieved and there was not 
1509a prior SYN packet sent it would filter that packet and not let it in. The correct sequence of steps are known and if the sequence or state is incorrect then it is dropped. 
1510
1511
1512Packets in a stateful inspection firewall are queued and then analyzed at all OSI layers, providing a more complete inspection of the data. By examining the state and 
1513context of the incoming data packets, it helps to track the protocols that are considered "connectionless", such as UDP-based applications and Remote Procedure Calls 
1514(RPC). 
1515
1516
1517
15182.C.3 Gateways, routers, and switches architecture (e.g. access control, segmentation, out-of-band management, OSI layers) 
1519A gateway is used to connect two networks using dissimilar protocols at the lower layers or it could also be at the highest level of the protocol stack. 
1520A bridge operates at the data link layer. Bridges are used to connect two separate networks to form a logical network. They must have storage capacity to store frames and 
1521act as a store-and-forward device. Bridges operate at the data link layer by examining the media access control header of a data packet. Routers are switching devices that 
1522operate at the network layer by examining network addresses. Repeaters work at the physical layer and amplify transmission signals to reach remote devices by taking a 
1523signal from a LAN. Gateways provide access paths to foreign networks. 
1524
1525
1526
1527
1528
1529
1530
1531A router is a network layer device for which the two connecting networks must have the same network layer protocol. Routers are switching devices that operate at the 
1532network layer (layer 3) by examining network addresses. 
1533A brouter is essentially a bridge with some routing functionality. 
1534Repeaters offer the simplest form of connectivity. They regenerate received electrical signals at their original strength between cable segments. Bridges are devices used to 
1535connect similar or dissimilar LANs together to form an extended LAN. Routers provide packet routing between network segments. Brouter are devices that combine router 
1536and bridge functionality. 
1537Switches primarily operate at the data link layer (layer 2), although intelligent, extremely fast Layer 3 switching techniques are being more frequently used. 
1538
1539
1540"First generation firewall" is the correct answer.  The first types of firewalls were packet filtering firewalls.  It is the most basic firewall making access decisions based on 
1541ACL's.  It will filter traffic based on source IP and port as well as destination IP and port.  It does not understand the context of the communication and inspects every single 
1542packet one by one without understanding the context of the connection.  
1543An important point with packet filtering firewalls is their speed and flexibility, as well as capacity to block denial-of-service and related attacks, makes them ideal for 
1544placement at the outermost boundary with and untrusted network. Other choices represent weaknesses of packet filtering firewalls. 
1545Packet filtering firewalls are essentially routing devices that include access control functionality for system addresses and communication sessions. This type of firewall is 
1546considered a first generation firewall and can operate at either the network of transport layer of the OSI model. 
1547
1548
1549"Second generation firewall" is incorrect.  The second generation of firewall were Proxy based firewalls.  Under proxy based firewall you have Application Level Proxy and 
1550also the Circuit-level proxy firewall.  The application level proxy is very smart and understand the inner structure of the protocol itself.  The Circui-Level Proxy is a generic 
1551proxy that allow you to proxy protocols for which you do not have an Application Level Proxy.  This is better than allowing a direct connection to the net.  Today a great 
1552example of this would be the SOCKS protocol.   
1553"Data's origin" is the correct answer.  The application firewall (proxy) relays the traffic from a trusted host running a specific application to an untrusted server.  It will 
1554appear to the untrusted server as if the request originated from the proxy server. 
1555"Third generation firewall" is incorrect.  The third generation firewall is the Stateful Inspection firewall.  This type of firewall makes use of a state table to maintain the 
1556context of connections being established.   
1557"Fourth generation firewall" is incorrect.   The fourth generation firewall is the dynamic packet filtering firewall. 
1558Firewalls can protect a network at multiple layers of the OSI models, however most of the firewalls do not have the ability to monitor the payload of the packets and see if 
1559an application level attack is taking place.  
1560Today there are a new breed of firewall called Unified Threat Managers or UTM. They are a collection of products on a single computer and not necessarily a typical 
1561firewall. A UTM can address all of the layers but typically a firewall cannot.  
1562Firewalls are security checkpoints at the boundaries of internal networks through which every packet must pass and be inspected, hence they create bottlenecks between 
1563the internal and external networks. But since external connections are relatively slow compared to modern computers, the latency caused by this bottleneck can almost be 
1564transparent.  
1565By implementing the concept of border security, they centralize security services in machines optimized and dedicated to the task, thus relieving the other hosts on the 
1566network from that function. 
1567
1568
1569
1570
1571
1572
1573
1574
1575The dynamic packet filtering firewall is able to create ACL's on the fly to allow replies on dynamic ports (higher than 1023). 
1576
1577
1578One the most secure implementations of firewall architectures is the screened-subnet firewall. It employs two packet-filtering routers and a bastion host. Like a 
1579screened host firewall, this firewall supports both packet-filtering and proxy services. 
1580
1581
1582IDS 
1583
1584The deployment of network-based IDSs has little impact upon an existing network. Network-based IDSs are usually passive devices that listen on a network wire without 
1585interfering with the normal operation of a network. Thus, it is usually easy to retrofit a network to include network-based IDSs with minimal effort. 
1586Network-based IDSs are not vulnerable to attacks is not true, even thou network-based IDSs can be made very secure against attack and even made invisible to many 
1587attackers they still have to read the packets and sometimes a well crafted packet might exploit or kill your capture engine. 
1588Network-based IDSs are well suited for modern switch-based networks is not true as most switches do not provide universal monitoring ports and this limits the monitoring 
1589range of a network-based IDS sensor to a single host. Even when switches provide such monitoring ports, often the single port cannot mirror all traffic traversing the switch.  
1590Most network-based IDSs can automatically indicate whether or not an attack was successful is not true as most network-based IDSs cannot tell whether or not an attack 
1591was successful; they can only discern that an attack was initiated. This means that after a network-based IDS detects an attack, administrators must manually investigate 
1592each attacked host to determine whether it was indeed penetrated. 
1593Network-based ID systems: 
1594- Commonly reside on a discrete network segment and monitor the traffic on that network segment 
1595- Usually consist of a network appliance with a Network Interface Card (NIC) that is operating in promiscuous mode and is intercepting and analyzing the network packets in 
1596real time 
1597"A passive NIDS takes advantage of promiscuous mode access to the network, allowing it to gain visibility into every packet traversing the network segment. This allows the 
1598system to inspect packets and monitor sessions without impacting the network, performance, or the systems and applications utilizing the network." 
1599
1600
1601A HIDS does not consume large amounts of system resources is the correct choice.  HIDS can consume inordinate amounts of CPU and system resources in order to 
1602function effectively, especially during an event. 
1603All the other answers are characteristics of HIDSes 
1604A HIDS can: 
1605- scrutinize event logs, critical system files, and other auditable system resources; 
1606- look for unauthorized change or suspicious patterns of behavior or activity 
1607- can send alerts when unusual events are discovered 
1608
1609
1610IDS: 
1611Communications is the component of an alarm that delivers alerts through a variety of channels such as email, pagers, instant messages and so on. 
1612
1613
1614
1615
1616
1617
1618An Enunciator is the component of an alarm that uses business logic to compose the content and format of an alert and determine the recipients of that alert.  
1619A sensor is a fundamental component of IDS alarms. A sensor detects an event and produces an appropriate notification. 
1620Active and passive IDS 
1621An active IDS (now more commonly known as an intrusion prevention system — IPS) is a system that's configured to automatically block suspected attacks in progress 
1622without any intervention required by an operator. IPS has the advantage of providing real-time corrective action in response to an attack but has many disadvantages as 
1623well. An IPS must be placed in-line along a network boundary; thus, the IPS itself is susceptible to attack. Also, if false alarms and legitimate traffic haven't been properly 
1624identified and filtered, authorized users and applications may be improperly denied access. Finally, the IPS itself may be used to effect a Denial of Service (DoS) attack by 
1625intentionally flooding the system with alarms that cause it to block connections until no connections or bandwidth are available. 
1626A passive IDS is a system that's configured only to monitor and analyze network traffic activity and alert an operator to potential vulnerabilities and attacks. It isn't capable 
1627of performing any protective or corrective functions on its own. The major advantages of passive IDSes are that these systems can be easily and rapidly deployed and are 
1628not normally susceptible to attack themselves.  
1629Network-based and host-based IDS 
1630A network-based IDS usually consists of a network appliance (or sensor) with a Network Interface Card (NIC) operating in promiscuous mode and a separate management 
1631interface. The IDS is placed along a network segment or boundary and monitors all traffic on that segment. 
1632A host-based IDS requires small programs (or agents) to be installed on individual systems to be monitored. The agents monitor the operating system and write data to log 
1633files and/or trigger alarms. A host-based IDS can only monitor the individual host systems on which the agents are installed; it doesn't monitor the entire network.  
1634Knowledge-based and behavior-based IDS 
1635A knowledge-based (or signature-based) IDS references a database of previous attack profiles and known system vulnerabilities to identify active intrusion attempts. 
1636Knowledge-based IDS is currently more common than behavior-based IDS. 
1637Statistical analysis-based (also called behaviour-based) intrusion detection is characterized with a higher rate of false positives, as opposed to knowledge-based intrusion 
1638detection. Host-based and network-based intrusion detection are common implementations, not conceptual approaches. 
1639
1640
1641OSI SESSION LAYER - Layer 5 of the OSI model is the Session Layer.   This layer provides a logical persistent connection between peer hosts. A session is analogous to a 
1642conversation that is necessary for applications to exchange information.  
1643
1644
1645The sesstion layer is responsible for establishing, managing, and closing end-to-end connections, called sessions, between applications located at different network 
1646endpoints. Dialogue control management provided by the session layer includes full-duplex, half-duplex, and simplex communications. Session layer management also 
1647helps to ensure that multiple streams of data stay synchronized with each other, as in the case of multimedia applications like video conferencing, and assists with the 
1648prevention of application related data errors.  
1649The session layer is responsible for creating, maintaining, and tearing down the session.  
1650Three modes are offered:  
1651(Full) Duplex: Both hosts can exchange information simultaneously, independent of each other. 
1652Half Duplex: Hosts can exchange information, but only one host at a time.  
1653
1654
1655
1656
1657
1658
1659
1660
1661Simplex: Only one host can send information to its peer. Information travels in one direction only. 
1662
1663
1664The TCP/IP protocol model defines four layers:  
1665Application,  
1666
1667
1668Host-to-host 
1669The host-to-host layer provides for reliable end-to-end communications, ensures the data's error-free delivery, handles the data's packet sequencing, and maintains the 
1670data's integrity. It is comparable to the transport layer of the OSI model. 
1671
1672
1673Internet 
1674
1675
1676Network access.  
1677The session layer is defined in the OSI/ISO model. 
1678
1679
1680There are six basic security services defined by the OSI:  
1681•   Authentication,  
1682•   access control,  
1683•   data confidentiality,  
1684•   data integrity,  
1685•   nonrepudiation, and  
1686•   logging and monitoring. 
1687
1688
1689OSI LAYER 1: 
1690The physical layer (layer 1) defines the X.24, V.35, X.21 and HSSI standard interfaces. 
1691
1692
1693
1694OSI LAYER 2: 
1695PPP 
1696RARP 
1697L2F 
1698The Data Link layer provides data transport across a physical link. It handles physical addressing, network topology, line discipline, error notification, orderly delivery of 
1699frames, and optional flow control. 
1700
1701
1702
1703
1704
1705
1706
1707The Data Link layer of the OSI/ISO model provides SLIP, CSLIP and PPP protocol. 
1708Layer 2 (Data Link layer) transfers information to the other end of the physical link. It handles physical addressing, network topology, error notification, delivery of frames 
1709and flow control. 
1710
1711
1712OSI LAYER 3: 
1713ICMP 
1714The network layer contains the Internet Protocol (IP), the Internet Control Message Protocol (ICMP), and the Internet Group Management Protocol (IGMP) 
1715
1716
1717The main responsibility of the network layer is to insert information into the packet's header so that it can be properly routed. The protocols at the network layer must 
1718determine the best path for the packet to take. 
1719
1720
1721OSI LAYER 4: 
1722Services located in the transport layer (layer 4) both segment and reassemble the data from upper-layer applications and unite it onto the same data stream, which 
1723provides end-to-end data transport services and establishes a logical connection between the sending host and destination host on a network. 
1724As you will see in the explanations below the session layer establish LOGICAL CONNECTIONS between NETWORK DEVICES  (not hosts) 
1725The TRANSPORT LAYER establish logical connection between the END POINTS of an internetwork, that is, the originating host and the destination host. 
1726Both does similar tasks but one does it between devices and the other does it between END POINTS hosts. 
1727
1728
1729OSI LAYER 6: 
1730Layer 6 Presentation - It is responsible for taking information from the "Application layer protocols" and putting it in a form suitable for the application to process. 
1731
1732
17332.C.4 Detection and response 
17342.C.5 Content monitoring, inspection and filtering (e.g. email, web, data) 
17352.C.6 Device Control 
1736
1737
17382.D Identify security design considerations and associated risks 
17392.D.1 Interoperability 
17402.D.2 Auditability (e.g. regulatory, legislative, forensic requirements, segregation, verifiability of high assurance systems) 
17412.D.3 Security configuration (e.g. baseline) 
17422.D.4 Remote access 
17432.D.5 Monitoring (e.g. sensor placement, time reconciliation, span of contro, record compatibility) 
17442.D.6 Network configuration (e.g. physical, logical, high availability) 
1745
1746
1747
1748
1749
1750
1751
17522.D.7 Operating environment (e.g. virtualization, cloud computing) 
17532.D.8 Secure sourcing strategy 
1754
1755
1756
1757
1758
1759
1760OTHER 
1761
1762
1763Incident Response Management - This management often consists of the following: 
1764- Coordinating the notification and distribution of information pertaining to the incident to the appropriate parties (those with a need to know) through a predefined 
1765escalation path 
1766- Mitigating risk to the enterprise by minimizing the disruptions to normal business activities and the costs associated with remediating the incident (including public 
1767relations) 
1768- Assembling teams of technical personnel to investigate the potential vulnerabilities and to resolve specific intrusions 
1769
1770
1771The purposes of RAID (Redundant Array of Inexpensive Disks) is to provide Redundancy and Higher Data Transfer performance. 
1772The purpose of RAID is Fault Tolerance. 
1773Basically, RAID separates the data into multiple units and stores it on multiple disks by using a process called "striping". 
1774The RAID Advisory Board has defined three classifications of RAID:  
1775Failure Resistant Disk Systems (FRDSs),  
1776Failure Tolerant Disk Systems,  
1777Disaster Tolerant Disk Systems. 
1778RAID Level 1 mirrors the data from one disk or set of disks by duplicating the data onto another disk or set of disks. 
1779RAID Levels 3 and 4 :- In this implementation, spare drives can be used to replace crashed drives. 
1780RAID Level 5 stripes the data and the parity information at the block level across all the drives in the set. 
1781RAID Level 5 :- The spare drives that replace the failed drives are usually hot swappable, meaning they can be replaced on the server while the system is up and running. 
1782A hardware RAID implementation is usually platform-independent. 
1783RAID levels 3 and 5 run faster on hardware. 
1784RAID systems are mostly concerned with availability and performance.   
1785Redundant array of inexpensive disks (RAID) are primarily used to implove speed, availability, and redundancy, not integrity.  They provide fault tolerance and protection 
1786against file server hard disk crashes.   
1787RAID 1 Mirroring has the highest cost per megabyte since every piece of data is written at two different locations simultaneously for redundancy purposes. 
1788The only difference is that level 3 is implemented at the byte level and level 4 is usually implemented at the block level. 
1789
1790
1791
1792
1793
1794
1795
1796RAID Level 2 :- It defines a disk drive system with 39 disks: 32 disks of user storage and seven disks of error recovery coding. 
1797
1798
1799Tape Arrays use a large device with multiple (sometimes 32 or 64) tapes that are configured as a single array. 
1800
1801
1802The Digital Linear Tape (DLT) is only 4mm in size, yet the compression techniques and head scanning process make it a large capacity and fast (5 Mbps) tape. 
1803Quarter Inch Cartridge drives (QIC). This format is mostly used for home/small office backups, has a small capacity, and is slow, but inexpensive. 
1804
1805
1806Differential Backup - Backup the files that have been modified since the last Full Backup. The archive bit does not change. Take more time while the backup phase is 
1807performed and take less time to restore.  
1808Incremental Backup - Backup all the files that have changed since the last Full Backup (the first time it is run after a full backup was previously completed) or Incremental 
1809Backup (for the second backup and subsequent backups) and sets the archive bit to 0. Take less time during the backup phase but it will take more time to restore. The 
1810incremental backup method only copies files that have been recently changed or added. Only files with their archive bit set are backed up. This method is fast and uses less 
1811tape space but has some inherent vulnerabilities, one being that all incremental backups need to be available and restored from the date of the last full backup to the 
1812desired date should a restore be needed. 
1813Hierarchical Storage Management (HSM) provides a continuous on-line backup by using optical or tape "jukeboxes," similar to WORMs. 
1814Hierarchical Storage Management (HSM) is commonly employed in very large data retrieval systems. 
1815
1816
1817
1818Mirroring, the system writes the data simultaneously to separate drives or arrays.  
1819The advantage of mirroring are minimal downtime, simple data recovery, and increased performance in reading from the disk.  
1820The disadvantage of mirroring is that both drives or disk arrays are processing in the writing to disks function, which can hinder system performance.  
1821Mirroring has a high fault tolerance and can be implemented either through a hardware RAID controller or through the operating system. Since it requires twice the disk 
1822space than actual data, mirroring is the less cost-efficient data redundancy strategy. 
1823
1824
1825DMZ = screened subnet. 
1826
1827
1828
1829BACKUPS: 
1830The purpose of a tape backup method is to protect and/or restore lost, corrupted, or deleted information, thereby preserving the data integrity and ensuring availability. 
1831All other choices could suffer from corruption and it might not be possible to restore the data without proper backups being done.  
1832Mirroring will preserve integrity and restore points in all cases of drive failure.  However, if you have corrupted data on the primary set of drives you may get corrupted 
1833data on the secondary set as well. 
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843Remote Journaling provides Continuous or periodic synchronized recording of transaction  data at a remote location  as a backup strategy. 
1844(http://www.businessdictionary.com/definition/remote-journaling.html)  With journaling there might be a gap of time between the data updates being send in batch at 
1845regular interval.  So some of the data could be lost. 
1846Database shadowing is synonymous with Mirroring but it only applies to databases, but not to information and data as a whole. 
1847
1848
1849
1850BootP was developed as a simple mechanism for allowing simple network terminals to load their operating system from a server over the LAN. Over time, it 
1851has expanded to allow centralized configuration of many aspects of a host's identity and behavior on the network. Note that DHCP, more complex, has 
1852replaced BootP over time. 
1853
1854
1855In general, the term packet applies to any message formatted as a packet, while the term datagram is generally reserved for packets of an "unreliable" service. 
1856
1857
1858A smurf attack occurs when an attacker sends a spoofed (IP spoofing) PING (ICMP ECHO) packet to the broadcast address of a large network (the bounce site). The 
1859modified packet containing the address of the target system, all devices on its local network respond with a ICMP REPLY to the target system, which is then saturated with 
1860those replies. An IP spoofing attack is used to convince a system that it is communication with a known entity that gives an intruder access. It involves modifying the source 
1861address of a packet for a trusted source's address. A teardrop attack consists of modifying the length and fragmentation offset fields in sequential IP packets so the target 
1862system becomes confused and crashes after it receives contradictory instructions on how the fragments are offset on these packets. A SYN attack is when an attacker floods 
1863a system with connection requests but does not respond when the target system replies to those requests. 
1864
1865
1866An IP spoofing attack is used to convince a system that it is communication with a known entity that gives an intruder access. It involves modifying the source address of 
1867a packet for a trusted source's address. A TCP sequence number attack involves hijacking a session between a host and a target by predicting the target's choice of an initial 
1868TCP sequence number. Piggybacking refers to an attacker gaining unauthorized access to a system by using a legitimate user's connection. A teardrop attack consists of 
1869modifying the length and fragmentation offset fields in sequential IP packets so the target system becomes confused and crashes after it receives contradictory instructions 
1870on how the fragments are offset on these packets. 
1871
1872
1873A TCP sequence number attack exploits the communication session which was established between the target and the trusted host that initiated the session. It involves 
1874hijacking the session between the host and the target by predicting the target's choice of an initial TCP sequence number. An IP spoofing attack is used to convince a system 
1875that it is communication with a known entity that gives an intruder access. It involves modifying the source address of a packet for a trusted source's address. A SYN attack 
1876is when an attacker floods a system with connection requests but does not respond when the target system replies to those requests. A smurf attack occurs when an 
1877attacker sends a spoofed (IP spoofing) PING (ICMP ECHO) packet to the broadcast address of a large network (the bounce site). The modified packet containing the address 
1878of the target system, all devices on its local network respond with a ICMP REPLY to the target system, which is then saturated with those replies. 
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888The Land attack involves the perpetrator sending spoofed packet(s) with the SYN flag set to the victim's machine on any open port that is listening. The packet(s) contain 
1889the same destination and source IP address as the host,  causing the victim's machine to reply to itself repeatedly. In addition, most systems experience a total freeze up, 
1890where as CTRL-ALT-DELETE fails to work, the mouse and keyboard become non operational and the only method of correction is to reboot via a reset button on the system 
1891or by turning the machine off.  
1892
1893
1894The Boink attack, a modified version of the original Teardrop and Bonk exploit programs, is very similar to the Bonk attack, in that it involves the perpetrator sending 
1895corrupt UDP packets to the host. It however allows the attacker to attack multiple ports where Bonk was mainly directed to port 53 (DNS).  
1896
1897
1898The Teardrop attack involves the perpetrator sending overlapping packets to the victim, when their machine attempts to re-construct the packets the victim's machine 
1899hangs.  
1900
1901
1902A Smurf attack is a network-level attack against hosts where a perpetrator sends a large amount of ICMP echo (ping) traffic at broadcast addresses, all of it having a 
1903spoofed source address of a victim. If the routing device delivering traffic to those broadcast addresses performs the IP broadcast to layer 2 broadcast function, most hosts 
1904on that IP network will take the ICMP echo request and reply to it with an echo reply each, multiplying the traffic by the number of hosts responding. On a multi-access 
1905broadcast network, there could potentially be hundreds of machines to reply to each packet. 
1906
1907
1908A teardrop attack consists of modifying the length and fragmentation offset fields in sequential IP packets so the target system becomes confused and crashes after it 
1909receives contradictory instructions on how the fragments are offset on these packets. A SYN attack is when an attacker floods a system with connection requests but does 
1910not respond when the target system replies to those requests. A smurf attack is an attack where the attacker spoofs the source IP address in an ICMP ECHO broadcast 
1911packet so it seems to have originated at the victim's system, in order to flood it with REPLY packets. A buffer overflow attack occurs when a process receives much more 
1912data than expected. 
1913
1914
1915Network Address Hijacking enables the intruder re-route data traffic from a network device to a personal machine. 
1916
1917
1918In computer networking, source routing allows a sender of a packet to specify the route the packet takes through the network. 
1919With source routing the entire path to the destination is known to the sender and is included when sending data. Source routing differs from most other routing in that the 
1920source makes most or all of the routing decisions for each router along the way. 
1921
1922
1923Urgent Pointer 
1924This could be a sign of covert channels being used in the bank network communications and should be investigated.  
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935The Urgent Pointer is used when some information has to reach the server ASAP. When the TCP/IP stack at the other end sees a packet using the Urgent Pointer set, it is 
1936duty bound to stop all ongoing activities and immediately send this packet up the stack for immediate processing.  Since the packet is plucked out of the processing queue 
1937and acted upon immediately, it is known as an Out Of Band (OOB)  packet and the data is called Out Of Band (OOB) data.  
1938The Urgent Pointer is usually used in Telnet, where an immediate response (e.g. the echoing of characters) is desirable. 
1939
1940
1941Covert Channels are not directly synonymous with backdoors.  A covert channel is simply using a communication protocol in a way it was not intended to be used or 
1942sending data without going through the proper access control mechanisms or channels.  For example, in a Mandatory Access Control systems a user at secret has found a 
1943way to communicate information to a user at Confidential without going through the normal channels. 
1944In this case the Urgent bit could be use for a few reasons:   
19451. It could be to attempt a Denial of service where the host receiving a packet with the Urgent bit set will give immediate attention to the request and will be in wait state 
1946until the urgent message is receive, if the sender does not send the urgent message then it will simply sit there doing nothing until it times out.  Some of the TCP/IP stacks 
1947used to have a 600 seconds time out, which means that for 10 minutes nobody could use the port.  By sending thousands of packet with the URGENT flag set, it would 
1948create a very effective denial of service attack. 
19492. It could be used as a client server application to transmit data back and forward without going through the proper channels.   It would be slow but it is possible to use 
1950reserved fields and bits to transmit data outside the normal communication channels. 
1951
1952
1953IP CLASSES: 
1954For Class A, the addresses are 0.0.0.0 - 127.255.255.255 
1955The lowest Class A address is represented in binary as 00000000.00000000.0000000.00000000  
1956
1957
1958For Class B networks, the addresses are 128.0.0.0 - 191.255.255.255. 
1959The lowest Class B address is represented in binary as 10000000.00000000.00000000.00000000 
1960
1961
1962For Class C, the addresses are 192.0.0.0 - 223.255.255.255 
1963The lowest Class C address is represented in binary as 11000000.00000000.00000000.00000000 
1964
1965
1966For Class D, the addresses are 224.0.0.0 - 239.255.255.255 (Multicast) 
1967The lowest Class D address is represented in binary as 11100000.00000000.00000000.00000000 
1968
1969
1970For Class E, the addresses are 240.0.0.0 - 255.255.255.255  (Reserved for future usage) 
1971The lowest Class E address is represented in binary as 11110000.00000000.00000000.00000000 
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982Misuse detectors compare system activity, looking for events or sets of events that match a predefined pattern of events that describe a known attack.  As the patterns 
1983corresponding to known attacks are called signatures, misuse detection is sometimes called "signature-based detection."  
1984The most common form of misuse detection used in commercial products specifies each pattern of events corresponding to an attack as a separate signature.  However, 
1985there are more sophisticated approaches to doing misuse detection (called "state-based" analysis techniques) that can leverage a single signature to detect groups of 
1986attacks. 
1987
1988
1989The actual IP address (IPv4) is composed of 32 bits. An IPv6 address is composed of 128 bits. 
1990
1991
1992Classification: 
1993According to the AIO 3rd edition, these are the necessary steps for a proper classification program: 
19941. Define classification levels. 
19952. Specify the criteria that will determine how data is classified. 
19963. Have the data owner indicate the classification of the data she is responsible for. 
19974. Identify the data custodian who will be responsible for maintaining data and its security level. 
19985. Indicate the security controls, or protection mechanisms, that are required for each classification level. 
19996. Document any exceptions to the previous classification issues. 
20007. Indicate the methods that can be used to transfer custody of the information to a different data owner. 
20018. Create a procedure to periodically review the classification and ownership. Communicate any changes to the data custodian. 
20029. Indicate termination procedures for declassifying the data. 
200310. Integrate these issues into the security-awareness program so that all employees understand how to handle data at different classification levels 
2004
2005
2006IPSec: 
2007In tunnel mode, the entire packet is encrypted and encased into an IPSec packet.  
2008In transport mode, only the datagram (payload) is encrypted, leaving the IP address visible within the IP header.  
2009Authentication mode and safe mode are not defined IPSec operational modes. 
2010IPSec Transport mode: 
2011•   Set-up when end-point is host or communications terminates at end-points  
2012•   If used in gateway-to-host communication, gateway must act as host  
2013•   When ESP is used for the security protocol, the hash is only applied to the upper layer protocols contained in the packet 
2014
2015
2016IPSec Tunnel mode: 
2017•   Fundamentally an IP tunnel with encryption and authentication 
2018
2019
2020
2021
2022
2023
2024
2025
2026•   Have two sets of IP headers  
2027•   Established for gateway service 
2028
2029
2030IPSec provides confidentiality and integrity to information transferred over IP networks through network (not transport) layer encryption and authentication. All other 
2031statements are correct. 
2032
2033
2034IP 
2035This IP address contains the information that aids in routing the information to the destination address.   It is an  identifier for a computer or device on a TCP/IP network. 
2036Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four 
2037numbers separated by periods. Each number can be zero to 255. For example, 1.160.10.240 could be an IP address.  
2038
2039
2040Within an isolated network, you can assign IP addresses at random as long as each one is unique. However, connecting a private network to the Internet requires using 
2041registered IP addresses (called Internet addresses) to avoid duplicates.  
2042The four numbers in an IP address are used in different ways to identify a particular network and a host on that network. Four regional Internet registries -- ARIN, RIPE NCC, 
2043LACNIC and APNIC -- assign Internet addresses from the following three classes. 
2044- Class A - supports 16 million hosts on each of 126 networks 
2045- Class B - supports 65,000 hosts on each of 16,000 networks 
2046- Class C - suports 254 hosts on each of 2 million networks  
2047The number of unassigned Internet addresses is running out, so a new classless scheme called CIDR is gradually replacing the system based on classes A, B, and C and is tied 
2048to adoption of IPv6.  
2049IP addresses do not protect resources from intrusion.  
2050Encapsulation is a technique used to add header information to the protocol data unit from the layer above.  
2051Broadcasts are packets that are transmitted to every node on a local network segment. 
2052
2053
2054If the protocol field has a value of 6 then it would indicate it was TCP. 
2055ICMP. Is incorrect because the value for an ICMP protocol would be 1. 
2056UDP. Is incorrect because the value for an UDP protocol would be 17. 
2057IGMP. Is incorrect because the value for an IGMP protocol would be 2. 
2058
2059
2060
2061Network File System (NFS) is a TCP/IP client/server application developed by Sun that enables different types of file systems to interoperate regardless of operating 
2062system or network architecture. 
2063
2064
2065
2066
2067
2068
2069
2070
2071Piggy Backing 
2072In security, piggybacking refers to when a person tags along with another person who is authorized to gain entry into a restricted area, or pass a certain.  The act may be 
2073legal or illegal, authorized or unauthorized, depending on the circumstances. However, the term more often has the connotation of being an illegal or unauthorized act. 
2074To describe the act of an unauthorized person who follows someone to a restricted area without the consent of the authorized person, the term tailgating is also used. 
2075"Tailgating" implies without consent (similar to a car tailgating another vehicle on the freeway), while "piggybacking" usually implies consent of the authorized person. 
2076Piggybacking came to the public's attention particularly in 1999, when a series of weaknesses were exposed in airport security. While a study showed that the majority of 
2077undercover agents attempting to pass through checkpoints, bring banned items on planes, or board planes without tickets were successful, piggybacking was revealed as 
2078one of the methods that was used in order to enter off-limits areas. 
2079Concealing 
2080Concealment (also called abscondence or hiding) is obscuring something from view or rendering it inconspicuous, the opposite of exposure.   A military term is CCD: 
2081camouflage (object looks like its surroundings), concealment (object cannot be seen), and deception (object looks like something else); in a broad sense, all three are forms 
2082of concealment. 
2083The objective of hiding is often to keep the presence of an object or person secret, but in other cases not the presence is a secret, but only the location. 
2084
2085
2086This can be a weakness for Callback systems. The modem calls the registered telephone number and if call forwarding is enabled, the call can be forwarded anywhere and 
2087the modem/system has no idea or control over that. 
2088A between-the-lines entry attack is a wire tap. This would not be a weakness specifically of a callback system because this type of attack could impact any dial-up system. 
2089
2090
2091The correct answer is 1024 to 49151 as it has been defined as REGISTERED PORTS by IANA. 
2092The other answers are not correct as they do not lie with in the range defined by IANA for registered ports. 
2093
2094
2095A bastion host is a special purpose computer on a network specifically designed and configured to withstand attack. The computer hosts a single application, for example 
2096a proxy server, and all other services are removed or limited to reduce the threat to the computer. It is hardened in this manner primarily due to its location and purpose, 
2097which is either on the outside of the firewall or in the DMZ and usually involves access from untrusted networks or computers. 
2098
2099
2100TCP Wrappers can control when a UDP server starts but has little control afterwards because UDP packets can be sent randomly. 
2101
2102
2103A SYN attack occurs when an attacker floods the target system's small "in-process" queue with connection requests, but it does not respond when the target system 
2104replies to those requests. This causes the target system to "time out" while waiting for the proper response, which makes the system crash or become unusable. A buffer 
2105overflow attack occurs when a process receives much more data than expected. One common buffer overflow attack is the ping of death, where an attacker sends IP 
2106packets that exceed the maximum legal length (65535 octets). A smurf attack is an attack where the attacker spoofs the source IP address in an ICMP ECHO broadcast 
2107packet so it seems to have originated at the victim's system, in order to flood it with REPLY packets. 
2108
2109
2110
2111
2112
2113
2114
2115
2116ARP table poisoning, also referred to as ARP cache poisoning, is the process of altering a system's ARP table so that it contains incorrect IP to MAC address mappings. This 
2117allows requests to be sent to a different device instead of the one it is actually intended for. It is an excellent way to fool systems into thinking that a certain device has a 
2118certain address so that information can be sent to and captured on an attacker's computer. 
2119
2120
2121Pivoting refers to method used by penetration testers that uses compromised system to attack other systems on the same network to avoid restrictions such as 
2122firewall configurations, which may prohibit direct access to all machines. For example, an attacker compromises a web server on a corporate network, the attacker can then 
2123use the compromised web server to attack other systems on the network. These types of attacks are often called multi-layered attacks. Pivoting is also known as island 
2124hopping. 
2125Pivoting can further be distinguished into proxy pivoting and VPN pivoting: 
2126Proxy pivoting generally describes the practice channeling traffic through a compromised target using a proxy payload on the machine and launching attacks from this 
2127computer.[1] This type of pivoting is restricted to certain TCP and UDP ports that are supported by the proxy.VPN pivoting enables the attacker to create an encrypted layer 
21282 tunnel into the compromised machine to route any network traffic through that target machine, for example to run a vulnerability scan on the internal network through 
2129the compromised machine, effectively giving the attacker full network access as if they were behind the firewall. 
2130
2131
2132A TCP Segment is the group of TCP data tramsmitted at the Transport Layer.  TCP is segment based network technology. 
2133The message is sent to the transport layer, where TCP does its magic on the data. The bundle of data is now a segment.  If the message is being transmitted over TCP, it is 
2134referred to as a “segment.” If it is being transmitted over UDP, it is referred to as a “datagram.   
2135Echo replies outbound should be dropped, not allowed.  
2136By allowing inbound echo requests and outbound echo replies, it makes it easier for attackers to learn about the internal network.  
2137The outbound echo request and inbound echo reply allow internal users to verify connectivity with external hosts. 
2138
2139
2140Explicit Congestion Notification (ECN) is an extension to the Internet Protocol and to the Transmission Control Protocol and is defined in RFC 3168 (2001).  ECN allows end- 
2141to-end notification of network congestion without dropping packets.  ECN is an optional feature that is only used when both endpoints support it and are willing to use it.  It 
2142is only effective when supported by the underlying network. 
2143Conventionally, TCP/IP networks signal congestion by dropping packets. When ECN is successfully negotiated, an ECN-aware router may set a mark in the IP header instead 
2144of dropping a packet in order to signal impending congestion. The receiver of the packet echoes the congestion indication to the sender, which reduces its transmission rate 
2145as though it detected a dropped packet. 
2146The network layer provides switching and routing technologies, creating logical paths, known as virtual circuits, for transmitting data from node to node. Routing and 
2147forwarding are functions of this layer, as well as addressing, internetworking, error handling, congestion control and packet sequencing. 
2148
2149
2150The MAC address is 48 bits long, 24 of which identify the vendor, as provided by the IEEE. The other 24 bits are provided by the vendor. 
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
21623A Identify requirements (e.g. confidentiality, integrity, non-repudiation). 
2163Cryptography is a detective control in the fact that it allows the detection of fraudulent insertion, deletion or modification. It also is a preventive control is the fact that it prevents disclosure, but it usually does 
2164not offers any means of detecting disclosure. 
2165The cryptography domain addresses the principles, means, and methods of disguising information to ensure its integrity, confidentiality, and authenticity. Unlike the other domains, cryptography does not 
2166completely support the standard of availability.  
2167
2168
2169Availability  
2170Cryptography supports all three of the core principles of information security. Many access control systems use cryptography to limit access to systems through the use of passwords. Many token-based 
2171authentication systems use cryptographic-based hash algorithms to compute one-time passwords. Denying unauthorized access prevents an attacker from entering and damaging the system or network, 
2172thereby denying access to authorized users if they damage or currupt the data.  
2173
2174
2175Confidentiality  
2176Cryptography provides confidentiality through altering or hiding a message so that ideally it cannot be understood by anyone except the intended recipient.  
2177
2178
2179Integrity  
2180Cryptographic tools provide integrity checks that allow a recipient to verify that a message has not been altered. Cryptographic tools cannot prevent a message from being altered, but they are effective to 
2181detect either intentional or accidental modification of the message.  
2182
2183
2184Additional Features of Cryptographic Systems In addition to the three core principles of information security listed above, cryptographic tools provide several more benefits.  
2185
2186
2187Nonrepudiation  
2188In a trusted environment, the authentication of the origin can be provided through the simple control of the keys. The receiver has a level of assurance that the message was encrypted by the sender, and the 
2189sender has trust that the message was not altered once it was received. However, in a more stringent, less trustworthy environment, it may be necessary to provide assurance via a third party of who sent a 
2190message and that the message was indeed delivered to the right recipient. This is accomplished through the use of digital signatures and public key encryption. The use of these tools provides a level of 
2191nonrepudiation of origin that can be verified by a third party.  
2192
2193
2194Once a message has been received, what is to prevent the recipient from changing the message and contesting that the altered message was the one sent by the sender? The nonrepudiation of delivery prevents 
2195a recipient from changing the message and falsely claiming that the message is in its original state. This is also accomplished through the use of public key cryptography and digital signatures and is verifiable by a 
2196trusted third party.  
2197
2198
2199Authentication  
2200Authentication is the ability to determine if someone or something is what it declares to be. This is primarily done through the control of the keys, because only those with access to the key are able to encrypt a 
2201message. This is not as strong as the nonrepudiation of origin, which will be reviewed shortly Cryptographic functions use several methods to ensure that a message has not been changed or altered. These 
2202include hash functions, digital signatures, and message authentication codes (MACs). The main concept is that the recipient is able to detect any change that has been made to a message, whether accidentally 
2203or intentionally.  
2204
2205
2206Access Control  
2207Through the use of cryptographic tools, many forms of access control are supported—from log-ins via passwords and passphrases to the prevention of access to confidential files or messages. In all cases, access 
2208would only be possible for those individuals that had access to the correct cryptographic keys. 
2209NOTE FROM CLEMENT: 
2210As you have seen this question was very recently updated with the latest content of the Official ISC2 Guide (OIG) to the CISSP CBK, Version 3. 
2211
2212
2213
2214
2215
2216
2217
2218
2219Myself, I agree with most of you that cryptography does not help on the availability side and it is even the contrary sometimes if you loose the key for example.  In such case you would loose access to the data 
2220and negatively impact availability.   But the ISC2 is not about what I think or what you think, they have their own view of the world where they claim and state clearly that cryptography does address availability 
2221even thou it does not fully address it. 
2222They look at crypto as the ever emcompassing tool it has become today.  Where it can be use for authentication purpose for example where it would help to avoid corruption of the data through illegal access by 
2223an unauthorized user. 
2224The question is worded this way in purpose, it is VERY specific to the CISSP exam context where ISC2 preaches that cryptography address availability even thou they state it does not fully address it.   This is 
2225something new in the last edition of their book and something you must be aware of. 
2226Strong encryption refers to an encryption process that uses at least a 128-bit key. 
2227
2228
2229Historically, a code refers to a cryptosystem that deals with linguistic units: words, phrases, sentences, and so forth. Codes are only useful for specialized circumstances where the message to transmit has an 
2230already defined equivalent ciphertext word. 
2231
2232
2233The European Union on Electronic Signatures deal with Non repudiation. 
2234
2235
2236
2237
2238KEY LENGTH - since a large keyspace allows for more possible keys it is the BEST option here.  
2239The objective is to perform the maximum number of possible different keys generated, thus providing more security to the ciphering making harder  for intruders to figure them out. 
2240The One Time Pad, the Gilbert Cipher, The Vernam Cipher  
2241One time pad is the best scenario in cryptography, it is known as the unbreakable cipher.  Since a key of the same size as the message size will be used only once and then it is destroyed and never reused.  
2242This is most likely a theorical scenario only, we should use the highiest amount of bits and larger keysize so the combination resulted from the algorith used will be higher.  This would increase an attacker’s 
2243chances of figuring out the key value and deciphering the protected information. 
2244
2245
2246Hybrid Encryption Methods are when Asymmetric and Symmetric Algorithms used together. In the hybrid approach, the two technologies are used in a complementary manner, with each performing a 
2247different function. A symmetric algorithm creates keys that are used for encrypting bulk data, and an asymmetric algorithm creates keys that are used for automated key distribution. 
2248
2249
2250SYMMETRIC VS ASYMMETRIC Performance 
2251Because of the amount of computation involved in public key cryptography, a DES hardware implementation of secret key cryptography is on the order of 1000 to 10000 times faster than RSA public key 
2252cryptography. 
2253It is important to understand WHY it is faster and NOT only that it is faster.   Symmetric uses binary addition of bits, substitution, permutation, shifing columns, shifing rows, which requires very little processing 
2254power.  Asymmetric uses very complex mathematical problems such as the Discrete Logarithm problem in a finite field,  factoring large numbers into the two prime numbers used to create the large numbers, 
2255which all requires a lot of processsing power. 
2256So SPEED is definitively an advantage of Symmetric ciphers and this is WHY the bulk of the data is always encrypted using Symmetric ciphers versus Asymmetric ciphers.  
2257Sometimes even within the same book there are contradictions between authors as far as the exact number of times it would be faster.  Know WHY it is faster and where they would be used as this is the 
2258important thing to know for the purpose of the exam.  
2259The confusion often times comes from the fact that books do not specify if it is hardware or software implementation.  The RSA website does specify the following: 
2260By comparison, DES is much faster than RSA. In software, DES is generally at least 100 times as fast as RSA. In hardware, DES is between 1,000 and 10,000 times as fast, depending on the implementation.  
2261So if we do not know if software or hardware is being use, it is hard to make sense of the question.  The answer really depend on the implementation and whether or not it is software or hardware. 
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273The keyspace size uses a simple formula which is 2 the power of of the key size or in this case 2 to the power of 8. 
2274
2275
22763B Determine usage (e.g. intransit, at rest) 
22773C Identify Cryptographic design considerations and constraints 
2278
2279
2280
2281SYMMETRIC 
2282
2283When using symmetric cryptography, both parties will be using the same key for encryption and decryption. Symmetric cryptography is generally fast and can be hard to break, but it offers limited overall 
2284security in the fact that it can only provide confidentiality. 
2285
2286
2287
2288DES  - block 
2289
2290NSA took the 128-bit algorithm Lucifer that IBM developed, reduced the key size to 64 bits and with that developed DES. 
2291Data Encryption Standard (DES) is a symmetric key algorithm. Originally developed by IBM, under project name Lucifer, this 128-bit algorithm was accepted by the NIST in 1974, but the total key size was reduced to 
229264 bits, 56 of which make up the effective key, plus and extra 8 bits for parity. It somehow became a national cryptographic standard in 1977, and an American National Standard Institute (ANSI) standard in 1978.  
2293The characters are put through 16 rounds of transposition and substitution functions. Triple DES uses 48 rounds. Triple DES encrypts a message three times. This encryption can be accomplished in 
2294several ways. The most secure form of triple DES is when the three encryptions are performed with three different keys. 
2295Substitution is not a mode of DES. 
2296There is no DES mode called DES-EEE1.  It does not exist. 
2297
2298
2299The following are the correct modes for triple-DES (3DES):  
2300DES-EEE3 uses three keys for encryption and the data is encrypted, encrypted, encrypted;  
2301DES-EDE3 uses three keys and encrypts, decrypts and encrypts data. THE MOST SECURE!!! Triple DES with three distinct keys is the most secure form of triple-DES encryption. It can either be DES-EEE3 
2302(encrypt-encrypt-encrypt) or DES-EDE3 (encrypt-decrypt-encrypt). DES-EDE1 is not defined and would mean using a single key to encrypt, decrypt and encrypt again, equivalent to single DES. DES-EEE4 is not 
2303defined and DES-EDE2 uses only 2 keys (encrypt with first key, decrypt with second key, encrypt with first key again). 
2304DES-EEE2 and DES-EDE2 are the same as the previous modes, but the first and third operations use the same key. 
2305
2306
2307
2308DES (BLOCK CIPHER) operates in four mode:  
2309a) Cipher Block Chaining (CBC)  
2310The previous DES output is used as input. This is a characteristic of Cipher Block Chaining. Cipher Block Chaining uses the output from the previous block to encrypt the next block. 
2311CBC mode of operation was invented by IBM in 1976. In the cipher-block chaining (CBC) mode, each block of plaintext is XORed with the previous ciphertext block before being encrypted. This way, each 
2312ciphertext block is dependent on all plaintext blocks processed up to that point. Also, to make each message unique, an initialization vector must be used in the first block.  
2313CBC is a block cipher system in which the first plain text data block is exclusive-ORed with a block of pseudo-random data prior to being processed through the DES. The resulting cipher text block is then 
2314exclusive-ORed with the next plain text data block to form the next input block to the DES, thus chaining together blocks of cipher text. The chaining of cipher text blocks provides an error extension 
2315characteristic which is valuable in protecting against fraudulent data alteration. A CBC authentication technique is described in Appendix F.  
2316The CBC mode produces the same cipher text whenever the same plain text is encrypted using the same key and IV. Users who are concerned about this characteristic should incorporate a unique identifier (e.g., 
2317a one-up counter) at the beginning of each CBC message within a cryptographic period in order to insure unique cipher text. If the key and the IV are the same and no identifier precedes each message, messages 
2318that have the same beginning will have the same cipher text when encrypted in the CBC mode until the blocks that differ in the two messages are encrypted.  
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328Since the CBC mode is a block method of encryption, it must operate on 64-bit data blocks. Partial data blocks (blocks of less than 64 bits) require special handling. One method of encrypting a final partial data 
2329block of a message is described below. Others may be defined for special applications. 
2330
2331
2332b) Electronic Code Book (ECB)  
2333A given block of plaintext and a given key will always produce the same ciphertext. BEST FOR DATABASES. Because ECB works with blocks of data independently, data within files does not have to be encrypted 
2334in a certain order. This is very helpful when using encryption in databases. A database has different pieces of data accessed in a random fashion.  If it is encrypted with ECB mode, then any record or table can be 
2335added, encrypted, deleted, or decrypted independently of any other table or record.  
2336It is important to note that ECB does not offer randomness and should NOT be used to encrypt large quantity of data. 
2337The Electronic Codebook (ECB) mode is a basic, block, cryptographic method which transforms 64 bits of input to 64 bits of output u specified in FIPS PUB 46.  
2338The analogy to a codebook arises because the same plain text block always produces the same cipher text block for a given cryptographic key. Thus a list (or codebook) of plain text blocks and corresponding 
2339cipher text blocks theoretically could be constructed for any given key. In electronic implementation the codebook entries are calculated each time for the plain text to be encrypted and, inversely, for the cipher 
2340text to be decrypted. 
2341Electronic Code Book A given block of plaintext and a given key will always produce the same ciphertext. 
2342
2343
2344
2345c) Cipher Feedback (CFB)  
2346Individual characters are encoded by combining output from earlier encryption routines with plaintext. This is a characteristic of Cipher Feedback. Cipher Feedback the ciphertext is run through a key-generating 
2347device to create the key for the next block of plaintext. The cipher feedback (CFB) mode, a close relative of CBC, makes a block cipher into a self-synchronizing stream cipher. Operation is very similar; in 
2348particular, CFB decryption is almost identical to CBC encryption performed in reverse. 
2349The CFB mode is a stream method of encryption in which the DES is used to generate pseudorandom bits which are exclusive-ORed with binary plain text to form cipher text. The cipher text is fed back to form 
2350the next DES input block. Identical messages that are encrypted using the CFB mode and different IVs will have different cipher texts. IVs that are shorter than 64 bits should be put in the least significant bits of 
2351the first DES input block and the unused, most significant, bits initialized to "0's."  
2352In the CFB mode, errors in any K-bit unit of cipher text will affect the decryption of the garbled cipher text and also the decryption of succeeding cipher text until the bits in error have been shifted out of the CFB 
2353input block. The first af fected K-bit unit of plain text will be garbled in exactly those places where the cipher text is in error. Succeeding decrypted plain text will have an average error rate of fifty percent until all 
2354errors have been shifted out of the DES input block. Assuming no additional errors are encountered during this time, the correct plain text will then be obtained. 
2355
2356
2357d) Output Feedback (OFB)   
2358The output feedback (OFB) mode makes a block cipher into a synchronous stream cipher. It generates keystream blocks, which are then XORed with the plaintext blocks to get the ciphertext. Just as with other 
2359stream ciphers, flipping a bit in the ciphertext produces a flipped bit in the plaintext at the same location.  This property allows many error correcting codes to function normally even when applied before 
2360encryption. 
2361The Output Feedback (OFB) mode is an additive stream cipher in which errors in the cipher text are not extended to cause additional errors in the decrypted plain text. One bit in error in the cipher text causes 
2362only one bit to be in error in the decrypted plain text. Therefore, this mode cannot be used for data authentication but is useful in applications where a few errors in the decrypted plain text are acceptable.  
2363In the OFB mode, the same K bits of the DES output block that are used to encrypt a K-bit unit of plain text are fed back for the next input block. This feedback is completely independent of all plain text and all 
2364cipher text. As a result, there is no error extension in OFB mode.  
2365If cryptographic synchronization is lost in the OFB mode, then cryptographic initialization must be performed. The OFB mode is not a self-synchronizing cryptographic mode. 
2366
2367
2368
2369
2370
2371AES – block 
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383The Rijndael algorithm, chosen as the Advanced Encryption Standard  (AES) to replace DES, can be categorized as an iterated block cipher with a variable block length and key length that can be independently 
2384chosen as 128, 160, 192, 224, and 256. 
2385Characteristic: 
2386•    It employs a round transformation that is comprised of three layers of distinct and invertible transformations.  
2387•    It is suited for high speed chips with no area restrictions. 
2388•    It could be used on a smart card. 
2389•    Rijndael does not support multiples of 64 bits but multiples of 32 bits in the range of 128 bits to 256 bits.  Key length could be 128, 160, 192, 224, and 256. 
2390•    The key sizes may be any multiple of 32 bits  
2391•    Maximum block size is 256 bits 
2392•    The key size does not have to match the block size 
2393
2394
2395The Rijndael algorithm was chosen by NIST as a replacement standard for DES.  
2396It is a block cipher with a variable block length and key length.  
2397It employs a round transformation that is comprised of three layers of distinct and invertible transformations:  
2398The non-linear layer, 
2399the linear mixing layer, and  
2400the key addition layer. 
2401The Rijndael algorithm is a new generation symmetric block cipher that supports key sizes of 128, 192 and 256 bits, with data handled in 128-bit blocks - however, in excess of AES design criteria, the block sizes 
2402can mirror those of the keys. Rijndael uses a variable number of rounds, depending on key/block sizes, as follows:  
240310 rounds if the key/block size is 128 bits  
240412 rounds if the key/block size is 192 bits  
240514 rounds if the key/block size is 256 bits 
2406
2407
2408The Rijndael Cipher  
2409Rijndael is a block cipher, designed by Joan Daemen and Vincent Rijmen as a candidate algorithm for the Advanced Encryption Standard (AES) in the United States of America. The cipher has a variable block 
2410length and key length. 
2411Rijndael can be implemented very efficiently on a wide range of processors and in hardware. 
2412The design of Rijndael was strongly influenced by the design of the block cipher Square.  
2413
2414
2415The Advanced Encryption Standard (AES) 
2416The Advanced Encryption Standard (AES) keys are defined to be either 128, 192, or 256 bits in accordance with the requirements of the AES.   
2417The number of rounds, or iterations of the main algorithm, can vary from 10 to 14 within the Advanced Encryption Standard (AES) and is dependent on the block size and key length.  128 bits keys uses 10 rounds 
2418or encryptions, 192 bits keys uses 12 rounds of encryption, and 256 bits keys uses 14 rounds of encryption.  
2419The low number of rounds has been one of the main criticisms of Rijndael, but if this ever becomes a problem the number of rounds can easily be increased at little extra cost performance wise by increasing the 
2420block size and key length. 
2421Range of key and block lengths in Rijndael and AES  
2422Rijndael and AES differ only in the range of supported values for the block length and cipher key length.  
2423For Rijndael, the block length and the key length can be independently specified to any multiple of 32 bits, with a minimum of 128 bits, and a maximum of 256 bits.   The support for block and key lengths 160 
2424and 224 bits was introduced in Joan Daemen and Vincent Rijmen, AES submission document on Rijndael, Version 2, September 1999 available at http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf    
2425AES fixes the block length to 128 bits, and supports key lengths of 128, 192 or 256 bits only. 
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438IDEA - block 
2439
2440is a block cipher and operates on 64 bit blocks of data with a 128-bit key. The data blocks are divided into 16 smaller blocks and each has 8 rounds of mathematical functions performed on it. It is 
2441used in the PGP encryption software. It is a SYMMETRIC algorithm. 
2442
2443
2444RC2 - block - works with 64-bit blocks and variable key lengths. RC2 with a 40-bit key size was treated favourably under US export regulations for cryptography. 
2445
2446
2447
2448RC5 - block is a symmetric encryption algorithm. It is a block cipher of variable block length, encrypts through integer addition, the application of a bitwise Exclusive OR (XOR), and variable rotations. 
2449
2450RC5 is a fast block cipher created by Ron Rivest and analyzed by RSA Data Security, Inc.  
2451It is a parameterized algorithm with a variable block size, a variable key size, and a variable number of rounds.  
2452Allowable choices for the block size are 32 bits (for experimentation and evaluation purposes only), 64 bits (for use a drop-in replacement for DES), and 128 bits.  
2453The number of rounds can range from 0 to 255, while the key can range from 0 bits to 2040 bits in size. 
2454Please note that some sources such as the latest Shon Harris book mentions that RC5 maximum key size is of 2048, not 2040 bits. I would definitively use RSA as the authoritative source which specifies a key of 
24552040 bits. It is an error in Shon's book. 
2456
2457
2458RC4 - stream 
2459
2460RC4 ' as it is an algorithm used for encryption and does not provide hashing functions , it is also commonly implemented ' Stream Ciphers '. RC4 was initially a trade secret, but in September 1994 a description of 
2461it was anonymously posted to the Cypherpunks mailing list.  It was soon posted on the sci.crypt newsgroup, and from there to many sites on the Internet.   The leaked code was confirmed to be genuine as its 
2462output was found to match that of proprietary software using licensed RC4.  Because the algorithm is known, it is no longer a trade secret.  The name RC4 is trademarked,  so RC4 is often referred to as ARCFOUR 
2463or ARC4 (meaning alleged RC4) to avoid trademark problems.  RSA Security has never officially released the algorithm; Rivest has, however, linked to the English Wikipedia article on RC4 in his own course notes.  
2464RC4 has become part of some commonly used encryption protocols and standards, including WEP and WPA for wireless cards and TLS. 
2465
2466
2467
2468RC6 – block - was designed to fix a flaw in RC5. RC6 proper has a block size of 128 bits and supports key sizes of 128, 192 and 256 bits, but, like RC5, it can be parameterised to support a wide 
2469variety of word-lengths, key sizes and number of rounds. 
2470
2471
2472Skipjack – block - Skipjack uses an 80-bit key to encrypt or decrypt 64-bit data blocks. It is an unbalanced Feistel network with 32 rounds.[3] It was designed to be used in secured phones. 
2473
2474
2475Blowfish - BLOCK - is a keyed, symmetric block cipher, designed in 1993 by Bruce Schneier and included in a large number of cipher suites and encryption products. Blowfish provides a good 
2476
2477encryption rate in software and no effective cryptanalysis of it has been found to date. However, the Advanced Encryption Standard now receives more attention. 
2478Schneier designed Blowfish as a general-purpose algorithm, intended as an alternative to the aging DES and free of the problems and constraints associated with other algorithms. At the time Blowfish was 
2479released, many other designs were proprietary, encumbered by patents or were commercial/government secrets. Schneier has stated that, "Blowfish is unpatented, and will remain so in all countries. The 
2480algorithm is hereby placed in the public domain, and can be freely used by anyone." 
2481Blowfish has a 64-bit block size and a variable key length from 32 bits up to 448 bits. 
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492STREAM CIPHER 
2493A stream cipher is a type of symmetric encryption algorithm that operates on continuous streams of plain text and is appropriate for hardware-based encryption due to their higher processing power 
2494requirement.  Stream ciphers can be designed to be exceptionally fast.   
2495A stream cipher encrypts individual bits, whereas a block cipher encrypts blocks of bits. Block ciphers are commonly implemented at the software level because they require less processing power. Stream 
2496ciphers, on the other hand, 
2497require more randomness and processing power, making them more suitable for hardware-level encryption.  
2498A strong stream cipher is characterized by the following: 
2499â–  Long portions of bit patterns without repeating patterns within keystream values. The keystream must generate random bits. 
2500â–  A keystream independent of the key. An attacker should not be able to determine the key value based on the keystream. 
2501â–  An unpredictable keystream. The keystream must generate statistically unpredictable bits. 
2502â–  An unbiased keystream. There should be as many 0s as there are 1s in the keystream. Neither should dominate.  
2503
2504
2505A stream cipher is a type of symmetric encryption algorithm that operates on continuous streams of plain text and is appropriate for hardware-based encryption.  
2506Stream ciphers can be designed to be exceptionally fast, much faster than any block cipher. A stream cipher generates what is called a keystream (a sequence of bits used as a key).  
2507Stream ciphers can be viewed as approximating the action of a proven unbreakable cipher, the one-time pad (OTP), sometimes known as the Vernam cipher. A one-time pad uses a keystream of completely 
2508random digits.  The keystream is combined with the plaintext digits one at a time to form the ciphertext. This system was proved to be secure by Claude Shannon in 1949. However, the keystream must be (at 
2509least) the same length as the plaintext, and generated completely at random. This makes the system very cumbersome to implement in practice, and as a result the one-time pad has not been widely used, 
2510except for the most critical applications. 
2511A stream cipher makes use of a much smaller and more convenient key — 128 bits, for example. Based on this key, it generates a pseudorandom keystream which can be combined with the plaintext digits in a 
2512similar fashion to the one-time pad. However, this comes at a cost: because the keystream is now pseudorandom, and not truly random, the proof of security associated with the one-time pad no longer holds: it 
2513is quite possible for a stream cipher to be completely insecure if it is not implemented properly as we have seen with the Wired Equivalent Privacy (WEP) protocol. 
2514Encryption is accomplished by combining the keystream with the plaintext, usually with the bitwise XOR operation. 
2515
2516
2517Synchronous stream ciphers 
2518In a synchronous stream cipher a stream of pseudo-random digits is generated independently of the plaintext and ciphertext messages, and then combined with the plaintext (to encrypt) or the ciphertext (to 
2519decrypt). In the most common form, binary digits are used (bits), and the keystream is combined with the plaintext using the exclusive or operation (XOR). This is termed a binary additive stream cipher. 
2520In a synchronous stream cipher, the sender and receiver must be exactly in step for decryption to be successful. If digits are added or removed from the message during transmission, synchronisation is lost. To 
2521restore synchronisation, various offsets can be tried systematically to obtain the correct decryption. Another approach is to tag the ciphertext with markers at regular points in the output. 
2522If, however, a digit is corrupted in transmission, rather than added or lost, only a single digit in the plaintext is affected and the error does not propagate to other parts of the message. This property is useful 
2523when the transmission error rate is high; however, it makes it less likely the error would be detected without further mechanisms. Moreover, because of this property, synchronous stream ciphers are very 
2524susceptible to active attacks: if an attacker can change a digit in the ciphertext, he might be able to make predictable changes to the corresponding plaintext bit; for example, flipping a bit in the ciphertext 
2525causes the same bit to be flipped in the plaintext. 
2526Self-synchronizing stream ciphers 
2527Another approach uses several of the previous N ciphertext digits to compute the keystream. Such schemes are known as self-synchronizing stream ciphers, asynchronous stream ciphers or ciphertext autokey 
2528(CTAK). The idea of self-synchronization was patented in 1946, and has the advantage that the receiver will automatically synchronise with the keystream generator after receiving N ciphertext digits, making it 
2529easier to recover if digits are dropped or added to the message stream. Single-digit errors are limited in their effect, affecting only up to N plaintext digits. 
2530An example of a self-synchronising stream cipher is a block cipher in cipher feedback (CFB) mode. 
2531
2532
2533BLOCK CIPHER 
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543In cryptography, a block cipher is a deterministic algorithm operating on fixed-length groups of bits, called blocks, with an unvarying transformation that is specified by a symmetric key. Block ciphers are 
2544important elementary components in the design of many cryptographic protocols, and are widely used to implement encryption of bulk data. 
2545Even a secure block cipher is suitable only for the encryption of a single block under a fixed key. A multitude of modes of operation have been designed to allow their repeated use in a secure way, commonly to 
2546achieve the security goals of confidentiality and authenticity. However, block ciphers may also be used as building blocks in other cryptographic protocols, such as universal hash functions and pseudo-random 
2547number generators. 
2548
2549
2550The Cesar cipher is a simple substitution cipher that involves shifting the alphabet three positions to the right.  
2551ROT13 is a substitution cipher that shifts the alphabet by 13 places.  
2552Polyalphabetic cipher refers to using multiple alphabets at a time.  
2553Transposition cipher - In cryptography, a transposition cipher is a method of encryption by which the positions held by units of plaintext (which are commonly characters or groups of characters) are shifted 
2554according to a regular system, so that the ciphertext constitutes a permutation of the plaintext. That is, the order of the units is changed. Mathematically a bijective function is used on the characters' positions 
2555to encrypt and an inverse function to decrypt: 
2556•    Rail Fence cipher 
2557•    Route cipher 
2558•    Columnar transposition 
2559•    Double transposition 
2560•    Myszkowski transposition 
2561•    Disrupted transposition 
2562
2563
2564
2565
2566ASYMMETRIC 
2567
2568RSA 
2569RSA can be used for encryption, key exchange, and digital signatures. 
2570The correct answer is ' RSA ' named after its inventors Ron Rivest , Adi Shamir and Leonard Adleman is based on the difficulty of factoring large prime numbers. 
2571Factoring a number means representing it as the product of prime numbers. Prime numbers, such as 2, 3, 5, 7, 11, and 13, are those numbers that are not evenly divisible by any smaller number, except 1. A non- 
2572prime, or composite number, can be written as the product of smaller primes, known as its prime factors. 665, for example is the product of the primes 5, 7, and 19. A number is said to be factored when all of its 
2573prime factors are identified. As the size of the number increases, the difficulty of factoring increases rapidly. 
2574
2575
2576PKCS #1: RSA Cryptography Standard 
2577This document provides recommendations for the implementation of public-key cryptography based on the RSA algorithm, covering the following aspects: cryptographic primitives; encryption schemes; 
2578signature schemes with appendix; ASN.1 syntax for representing keys and for identifying the schemes. 
2579
2580
2581The computations involved in selecting keys and in enciphering data are complex, and are not practical for manual use. However, using mathematical properties of modular arithmetic and a method known as 
2582computing in Galois fields, RSA is quite feasible for computer use. 
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596ECC – Elliptic curve cryptosystem 
2597
2598It is believed to require shorter keys for equivalent security. Some experts believe that ECC with key length 160 bits is equivalent to RSA with key length 1024 bits. It computes discrete logarithms of elliptic 
2599curves. Elliptic curves are rich mathematical structures that have shown usefulness in many different types of applications. An elliptic curve cryptosystem (ECC) provides much of the same functionality that RSA 
2600provides: digital signatures, secure key distribution,and encryption. One differing factor is ECC’s efficiency. ECC is more efficient that RSA and any other asymmetric algorithm. 
2601Elliptic Curve Cryptosystems (ECCs) computes discrete logarithms of elliptic curves. 
2602
2603
2604El Gamal  
2605
2606is based on the discrete logarithms in a finite field. El Gamal is a public key algorithm that can be used for digital signatures, encryption,and key exchange. It is based not on the difficulty of factoring large 
2607numbers but on calculating discrete logarithms in a finite field. El Gamal is actually an extension of the Diffie-Hellman algorithm. Although El Gamal provides the same type of functionality as some of the other 
2608asymmetric algorithms, its main drawback is performance. When compared to other algorithms, this algorithm is usually the slowest. 
2609El Gamal is based on the discrete logarithms in a finite field. 
2610
2611
2612
2613
2614HASHING 
2615
2616
2617'A Message Digest ' as when a hash algorithm is applied on a message , it produces a message digest. 
2618The other answers are incorrect because : 
2619A digital signature is a hash value that has been encrypted with a sender's private key. 
2620A ciphertext is a message that appears to be unreadable. 
2621A plaintext is a readable data. 
2622
2623
2624
2625SHA-1 
2626
2627The Secure Hash Algorithm (SHA-1) computes a fixed length message digest from a variable length input message. 
2628SHA-1 produces a 160 bit message digest or hash value.  From the nist.gov document referenced above: 
2629This standard specifies four secure hash algorithms, SHA-1, SHA-256, SHA-384, and SHA- 512. All four of the algorithms are iterative, one-way hash functions that can process a messageto produce a condensed 
2630representation called a message digest. These algorithms enable the determination of a message’s integrity: any change to the message will, with a very high probability, result in a different message digest. This 
2631property is useful in the generation and verification of digital signatures and message authentication codes, and in the generation of random numbers (bits).  
2632Each algorithm can be described in two stages: preprocessing and hash computation. Preprocessing involves padding a message, parsing the padded message into m-bit blocks, and setting initialization values to 
2633be used in the hash computation. The hash computation generates a message schedule from the padded message and uses that schedule, along with functions, constants, and word operations to iteratively 
2634generate a series of hash values. The final hash vlue generated by the hash computation is used to determine the message digest. 
2635The four algorithms differ most significantly in the number of bits of security that are provided or the data being hashed – this is directly related to the message digest length. When a secure hash algorithm is 
2636used in conjunction with another algorithm, there may be requirements specified elsewhere that require the use of a secure hash algorithm with a certain number of bits of security. For example, if a message is 
2637being signed with a digital signature algorithm that provides 128 bits of security, then that signature algorithm may require the use of a secure hash algorithm that also provides 128 bits of security (e.g., SHA- 
2638256). 
2639Additionally, the four algorithms differ in terms of the size of the blocks and words of data that are used during hashing. 
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650SHA-1 is a one-way hashing algorithms.  SHA-1 is a cryptographic hash function designed by the United States National Security Agency and published by the United States NIST as a U.S. Federal Information 
2651Processing Standard. SHA stands for "secure hash algorithm".   
2652The three SHA algorithms are structured differently and are distinguished as SHA-0, SHA-1, and SHA-2.  SHA-1 is very similar to SHA-0, but corrects an error in the original SHA hash specification that led to 
2653significant weaknesses. The SHA-0 algorithm was not adopted by many applications. SHA-2 on the other hand significantly differs from the SHA-1 hash function. 
2654SHA-1 is the most widely used of the existing SHA hash functions, and is employed in several widely used security applications and protocols. In 2005, security flaws were identified in SHA-1, namely that a 
2655mathematical weakness might exist, indicating that a stronger hash function would be desirable.  Although no successful attacks have yet been reported on the SHA-2 variants, they are algorithmically similar to 
2656SHA-1 and so efforts are underway to develop improved alternatives.  A new hash standard, SHA-3, is currently under development — an ongoing NIST hash function competition is scheduled to end with the 
2657selection of a winning function in 2012. 
2658SHA-1 produces a 160-bit message digest based on principles similar to those used by Ronald L. Rivest of MIT in the design of the MD4 and MD5 message digest algorithms, but has a more conservative design. 
2659
2660
2661MD5 - was also created by Ron Rivest and is the newer version of MD4. It still produces a 128-bit hash, but the algorithm is more complex, which makes it harder to break.MD5 was also created by Ron 
2662
2663Rivest and is the newer version of MD4. It still produces a 128-bit hash, but the algorithm is more complex, which makes it harder to break.MD5 added a fourth round of operations to be performed during the 
2664hashing functions and makes several of its mathematical operations carry out more steps or more complexity to provide a higher level of security. 
2665A hash algorithm (alternatively, hash "function") takes binary data, called the message, and produces a condensed representation, called the message digest. A cryptographic hash algorithm is a hash algorithm 
2666that is designed to achieve certain security properties. The Federal Information Processing Standard 180-3, Secure Hash Standard, specifies five cryptographic hash algorithms - SHA-1, SHA-224, SHA-256, SHA- 
2667384, and SHA-512 for federal use in the US; the standard was also widely adopted by the information technology industry and commercial companies.   
2668
2669
2670The MD5 Message-Digest Algorithm is a widely used cryptographic hash function that produces a 128-bit (16-byte) hash value.  Specified in RFC 1321,  MD5 has been employed in a wide variety of 
2671security applications, and is also commonly used to check data integrity.  MD5 was designed by Ron Rivest in 1991 to replace an earlier hash function, MD4.  An MD5 hash is typically expressed as a 32-digit 
2672hexadecimal number. 
2673
2674
2675However, it has since been shown that MD5 is not collision resistant; as such, MD5 is not suitable for applications like SSL certificates or digital signatures that rely on this property.  In 1996, a flaw was found 
2676with the design of MD5, and while it was not a clearly fatal weakness, cryptographers began recommending the use of other algorithms, such as SHA-1 - which has since been found also to be vulnerable.  In 
26772004, more serious flaws were discovered in MD5, making further use of the algorithm for security purposes questionable - specifically, a group of researchers described how to create a pair of files that share 
2678the same MD5 checksum.  Further advances were made in breaking MD5 in 2005, 2006, and 2007.  In December 2008, a group of researchers used this technique to fake SSL certificate validity, and US-CERT now 
2679says that MD5 "should be considered cryptographically broken and unsuitable for further use." and most U.S. government applications now require the SHA-2 family of hash functions. 
2680
2681
2682
2683MD2 - is a one-way hash function designed by Ron Rivest that creates a 128-bit message digest value. It is not necessarily any weaker than the other algorithms in the "MD" family, but it is much slower. 
2684
2685
2686
2687
2688HAVAL - is a one-way hashing algorithms.  HAVAL is a cryptographic hash function. Unlike MD5, but like most modern cryptographic hash functions, HAVAL can produce hashes of different lengths. HAVAL 
2689can produce hashes in lengths of 128 bits, 160 bits, 192 bits, 224 bits, and 256 bits. HAVAL also allows users to specify the number of rounds (3, 4, or 5) to be used to generate the hash. 
2690
2691
2692
2693
2694
2695
2696One-Time-PAD 
2697
2698
2699
2700
2701
2702
2703
2704
2705A one-time pad is an encryption scheme using a random key of the same size as the message and is used only once. It is said to be unbreakable, even with infinite resources. A running key cipher 
2706uses articles in the physical world rather than an electronic algorithm. Steganography is a method where the very existence of the message is concealed. Cipher block chaining is a DES operating mode. 
2707it is easy (but not necessarily quick) to compute the hash value for any given message 
2708it is infeasible to generate a message that has a given hash 
2709it is infeasible to modify a message without changing the hash 
2710it is infeasible to find two different messages with the same hash 
2711
2712
2713DoD Model layers: 
2714The Application Layer determines the identity of the communication partners and this is where Non-Repudiation service would be provided as well. 
2715
2716
2717network layer. Is incorrect because the Network Layer mostly has routing protocols, ICMP, IP, and IPSEC.  It it not a layer in the DoD Model.  It is called the Internet Layer within the DoD model. 
2718transport layer. Is incorrect because the Transport layer provides transparent transfer of data between end users.  This is called Host-to-Host on the DoD model but sometimes some books will call it Transport as 
2719well on the DoD model. 
2720data link layer. Is incorrect because the Data Link Layer defines the protocols that computers must follow to access the network for transmitting and receiving messages.  It is part of the OSI Model.  This does not 
2721exist on the DoD model, it is called the Link Layer on the DoD model. 
2722
2723
2724Digital Signature 
2725A digital signature directly addresses both confidentiality and integrity of the CIA triad. It does not directly address availability, which is what denial-of-service attacks.  
2726Digital Signature Standard (DSS) specifies a Digital Signature Algorithm (DSA) appropriate for applications requiring a digital signature, providing the capability to generate signatures (with the use of a private 
2727key) and verify them (with the use of the corresponding public key). 
2728DSS provides Integrity, digital signature and Authentication, but does not provide Encryption. 
2729
2730
2731The steps to create a Digital Signature are very simple: 
27321. You create a Message Digest of the message you wish to send 
27332. You encrypt the message digest using your Private Key which is the action of Signing 
27343. You send the Message along with the Digital Signature to the recipient 
2735To validate the Digital Signature the recipient will make use of the sender Public Key. Here are the steps: 
27361.  The receiver will decrypt the Digital Signature using the sender Publick Key producing a clear text message digest. 
27372.  The receiver will produce his own message digest of the message received. 
27383.  At this point the receiver will compare the two message digest (the one sent and the one produce by the receiver), if the two matches, it proves the authenticity of the message and it confirms that the 
2739message was not modified in transit validating the integrity as well.  Digital Signatures provides for Authenticity and Integrity only.  There is no confidentiality in place, if you wish to get confidentiality it would be 
2740needed for the sender to encrypt everything with the receiver public key as a last step before sending the message. 
2741
2742
2743
2744
2745A digital envelope for a recipient is a combination of encrypted data and its encryption key in an encrypted form that has been prepared for use of the recipient.  
2746It consists of a hybrid encryption scheme in sealing a message, by encrypting the data and sending both it and a protected form of the key to the intended recipient, so that one else can open the message.  
2747In PKCS #7, it means first encrypting the data using a symmetric encryption algorithm and a secret key, and then encrypting the secret key using an asymmetric encryption algorithm and the public key of the 
2748intended recipient. 
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760RFC 2828 (Internet Security Glossary) defines digital watermarking as computing techniques for inseparably embedding unobtrusive marks or labels as bits in digital data-text, graphics, images, video, or 
2761audio#and for detecting or extracting the marks later. The set of embedded bits (the digital watermark) is sometimes hidden, usually imperceptible, and always intended to be unobtrusive. It is used as a 
2762measure to protect intellectual property rights. Steganography involves hiding the very existence of a message. A digital signature is a value computed with a cryptographic algorithm and appended to a data 
2763object in such a way that any recipient of the data can use the signature to verify the data's origin and integrity. A digital envelope is a combination of encrypted data and its encryption key in an encrypted form 
2764that has been prepared for use of the recipient. 
2765
2766
2767Steganography is a secret communication where the very existence of the message is hidden. For example, in a digital image, the least significant bit of each word can be used to comprise a message without 
2768causing any significant change in the image. Key clustering is a situation in which a plaintext message generates identical ciphertext messages using the same transformation algorithm but with different keys. 
2769Cryptology encompasses cryptography and cryptanalysis. The Vernam Cipher, also called a one-time pad, is an encryption scheme using a random key of the same size as the message and is used only once. It is 
2770said to be unbreakable, even with infinite resources. 
2771
2772
2773
2774Known plaintext attack, the attacker has the plaintext and ciphertext of one or more messages. The goal is to discover the key used to encrypt the messages so that other messages can be deciphered and 
2775read. The known-plaintext attack (KPA) or crib is an attack model for cryptanalysis where the attacker has samples of both the plaintext and its encrypted version (ciphertext), and is at liberty to make use of 
2776them to reveal further secret information such as secret keys and code books. The term "crib" originated at Bletchley Park, the British World War II decryption operation. 
2777
2778
2779An analytic attack refers to using algorithm and algebraic manipulation weakness to reduce complexity. A statistical attack uses a statistical weakness in the design. A brute-force attack is a type of attack 
2780under which every possible combination of keys and passwords is tried. In a codebook attack, an attacker attempts to create a codebook of all possible transformations between plaintext and ciphertext under a 
2781single key. 
2782
2783
2784A Birthday attack is usually applied to the probability of two different messages using the same hash function producing a common message digest.  
2785The term "birthday" comes from the fact that in a room with 23 people, the probability of two of more people having the same birthday is greater than 50%. 
2786Linear cryptanalysis is a general form of cryptanalysis based on finding affine approximations to the action of a cipher. Attacks have been developed for block ciphers and stream ciphers. Linear cryptanalysis is 
2787one of the two most widely used attacks on block ciphers; the other being differential cryptanalysis.  
2788
2789
2790A Brute force attack or exhaustive key search is a strategy that can in theory be used against any encrypted data by an attacker who is unable to take advantage of any weakness in an encryption system 
2791that would otherwise make his task easier. It involves systematically checking all possible keys until the correct key is found. In the worst case, this would involve traversing the entire key space, also called  
2792search space. 
2793Countermeasure = Session keys - If we assume a crytpo-system with a large key (and therefore a large key space) a brute force attack will likely take a good deal of time - anywhere from several hours to 
2794several years depending on a number of variables. If you use a session key for each message you encrypt, then the brute force attack provides the attacker with only the key for that one message. So, if you are 
2795encrypting 10 messages a day, each with a different session key, but it takes me a month to break each session key then I am fighting a loosing battle. 
2796
2797
2798Differential Cryptanalysis is a potent cryptanalytic technique introduced by Biham and Shamir.  Differential cryptanalysis is designed for the study and attack of DES-like cryptosystems. A DES-like 
2799cryptosystem is an iterated cryptosystem which relies on conventional cryptographic techniques such as substitution and diffusion.   
2800Differential cryptanalysis is a general form of cryptanalysis applicable primarily to block ciphers, but also to stream ciphers and cryptographic hash functions. In the broadest sense, it is the study of how 
2801differences in an input can affect the resultant difference at the output. In the case of a block cipher, it refers to a set of techniques for tracing differences through the network of transformations, discovering 
2802where the cipher exhibits non-random behaviour, and exploiting such properties to recover the secret key. 
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814A chosen-ciphertext attack is one in which cryptanalyst may choose a piece of ciphertext and attempt to obtain the corresponding decrypted plaintext. This type of attack is generally most applicable to 
2815public-key cryptosystems. 
2816A chosen-ciphertext attack (CCA) is an attack model for cryptanalysis in which the cryptanalyst gathers information, at least in part, by choosing a ciphertext and obtaining its decryption under an unknown key. 
2817In the attack, an adversary has a chance to enter one or more known ciphertexts into the system and obtain the resulting plaintexts. From these pieces of information the adversary can attempt to recover the 
2818hidden secret key used for decryption. 
2819A number of otherwise secure schemes can be defeated under chosen-ciphertext attack. For example, the El Gamal cryptosystem is semantically secure under chosen-plaintext attack, but this semantic security 
2820can be trivially defeated under a chosen-ciphertext attack. Early versions of RSA padding used in the SSL protocol were vulnerable to a sophisticated adaptive chosen-ciphertext attack which revealed SSL session 
2821keys. Chosen-ciphertext attacks have implications for some self-synchronizing stream ciphers as well. Designers of tamper-resistant cryptographic smart cards must be particularly cognizant of these attacks, as 
2822these devices may be completely under the control of an adversary, who can issue a large number of chosen-ciphertexts in an attempt to recover the hidden secret key. 
2823
2824
2825Cryptanalytic attacks are generally classified into six categories that distinguish the kind of information the cryptanalyst has available to mount an attack. The categories of attack are listed here roughly in 
2826increasing order of the quality of information available to the cryptanalyst, or, equivalently, in decreasing order of the level of difficulty to the cryptanalyst. The objective of the cryptanalyst in all cases is to be 
2827able to decrypt new pieces of ciphertext without additional information. The ideal for a cryptanalyst is to extract the secret key.  
2828A ciphertext-only attack is one in which the cryptanalyst obtains a sample of ciphertext, without the plaintext associated with it. This data is relatively easy to obtain in many scenarios, but a successful 
2829ciphertext-only attack is generally difficult, and requires a very large ciphertext sample.  Such attack was possible on cipher using Code Book Mode where frequency analysis was being used and even thou only 
2830the ciphertext was available, it was still possible to eventually collect enough data and decipher it without having the key.  
2831
2832
2833A known-plaintext attack is one in which the cryptanalyst obtains a sample of ciphertext and the corresponding plaintext as well.  The known-plaintext attack (KPA) or crib is an attack model for 
2834cryptanalysis where the attacker has samples of both the plaintext and its encrypted version (ciphertext), and is at liberty to make use of them to reveal further secret information such as secret keys and code 
2835books. 
2836
2837
2838A chosen-plaintext attack is one in which the cryptanalyst is able to choose a quantity of plaintext and then obtain the corresponding encrypted ciphertext.  A chosen-plaintext attack (CPA) is an attack 
2839model for cryptanalysis which presumes that the attacker has the capability to choose arbitrary plaintexts to be encrypted and obtain the corresponding ciphertexts. The goal of the attack is to gain some further 
2840information which reduces the security of the encryption scheme. In the worst case, a chosen-plaintext attack could reveal the scheme's secret key. 
2841This appears, at first glance, to be an unrealistic model; it would certainly be unlikely that an attacker could persuade a human cryptographer to encrypt large amounts of plaintexts of the attacker's choosing. 
2842Modern cryptography, on the other hand, is implemented in software or hardware and is used for a diverse range of applications; for many cases, a chosen-plaintext attack is often very feasible. Chosen- 
2843plaintext attacks become extremely important in the context of public key cryptography, where the encryption key is public and attackers can encrypt any plaintext they choose. 
2844Any cipher that can prevent chosen-plaintext attacks is then also guaranteed to be secure against known-plaintext and ciphertext-only attacks; this is a conservative approach to security. 
2845Two forms of chosen-plaintext attack can be distinguished: 
2846* Batch chosen-plaintext attack, where the cryptanalyst chooses all plaintexts before any of them are encrypted. This is often the meaning of an unqualified use of "chosen-plaintext attack". 
2847
2848
2849* Adaptive chosen-plaintext attack, is a special case of chosen-plaintext attack in which the cryptanalyst is able to choose plaintext samples dynamically, and alter his or her choices based on the results 
2850of previous encryptions.  The cryptanalyst makes a series of interactive queries, choosing subsequent plaintexts based on the information from the previous encryptions.Non-randomized (deterministic) public 
2851key encryption algorithms are vulnerable to simple "dictionary"-type attacks, where the attacker builds a table of likely messages and their corresponding ciphertexts. To find the decryption of some observed 
2852ciphertext, the attacker simply looks the ciphertext up in the table. As a result, public-key definitions of security under chosen-plaintext attack require probabilistic encryption (i.e., randomized encryption). 
2853Conventional symmetric ciphers, in which the same key is used to encrypt and decrypt a text, may also be vulnerable to other forms of chosen-plaintext attack, for example, differential cryptanalysis of block 
2854ciphers. 
2855An adaptive-chosen-ciphertext is the adaptive version of the above attack. A cryptanalyst can mount an attack of this type in a scenario in which he has free use of a piece of decryption hardware, but is unable 
2856to extract the decryption key from it.  
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866An adaptive chosen-ciphertext attack (abbreviated as CCA2) is an interactive form of chosen-ciphertext attack in which an attacker sends a number of ciphertexts to be decrypted, then uses the results of these 
2867decryptions to select subsequent ciphertexts. It is to be distinguished from an indifferent chosen-ciphertext attack (CCA1). 
2868The goal of this attack is to gradually reveal information about an encrypted message, or about the decryption key itself. For public-key systems, adaptive-chosen-ciphertexts are generally applicable only when 
2869they have the property of ciphertext malleability — that is, a ciphertext can be modified in specific ways that will have a predictable effect on the decryption of that message. 
2870
2871
2872
2873Frequency Analysis 
2874Simple substitution and transposition ciphers are vulnerable to attacks that perform frequency analysis.  
2875
2876
2877In every language, there are words and patterns that are used more than others.  
2878Some patterns common to a language can actually help attackers figure out the transformation between plaintext and ciphertext, which enables them to figure out the key that was used to perform the 
2879transformation. Polyalphabetic ciphers use different alphabets to defeat frequency analysis.  
2880The ceasar cipher is a very simple substitution cipher that can be easily defeated and it does show repeating letters.   
2881Out of list presented, it is the Polyalphabetic cipher that would provide the best protection against simple frequency analysis attacks. 
2882
2883
2884
2885
2886Cross Certification 
2887
2888The correct answer is:  Creating trust between different PKIs More and more organizations are setting up their own internal PKIs. When these independent PKIs need to interconnect to allow for secure 
2889communication to take place (either between departments or different companies), there must be a way for the two root CAs to trust each other.  These two CAs do not have a CA above them they can both 
2890trust, so they must carry out cross certification. A cross certification is the process undertaken by CAs to establish a trust relationship in which they rely upon each other's digital certificates and public keys as if 
2891they had issued them themselves. When this is set up, a CA for one company can validate digital certificates from the other company and vice versa. 
2892Cross-certification is the act or process by which two CAs each certifiy a public key of the other, issuing a public-key certificate to that other CA, enabling users that are certified under different certification 
2893hierarchies to validate each other's certificate. 
2894
2895
2896
2897
2898In order to protect against fraud in electronic fund transfers (EFT), the Message Authentication Code (MAC), ANSI X9.9, was developed. The MAC is a check value, which is derived from the contents 
2899of the message itself, that is sensitive to the bit changes in a message. It is similar to a Cyclic Redundancy Check (CRC).  
2900The aim of message authentication in computer and communication systems is to verify that he message comes from its claimed originator and that it has not been altered in transmission. It is particularly 
2901needed for EFT Electronic Funds Transfer). The protection mechanism is generation of a Message Authentication Code (MAC), attached to the message, which can be recalculated by the receiver and will reveal 
2902any alteration in transit. One standard method is described in (ANSI, X9.9). Message authentication mechanisms an also be used to achieve non-repudiation of messages. 
2903
2904
2905A Message Authentication Code (MAC) is an authentication checksum derived by applying an authentication scheme, together with a secret key, to a message.  
2906Unlike digital signatures, MACs are computed and verified with the same key, so that they can only be verified by the intended recipient.  
2907There are four types of MACs:  
2908(1) unconditionally secure,  
2909(2) hash function based,  
2910(3) stream cipher-based and  
29114) block cipher-based. 
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922The correct answer is ' To detect any alteration of the message ' as the message digest is calculated and included in a digital signature to prove that the message has not been altered since the time it was 
2923created by the sender. 
2924
2925
2926A keyed hash also called a MAC (message authentication code) is used for integrity protection and authenticity. 
2927In cryptography, a message authentication code (MAC) is a generated value used to authenticate a message. A MAC can be generated by HMAC or CBC-MAC methods.  The MAC protects both a message’s 
2928integrity (by ensuring that a different MAC will be produced if the message has changed) as well as its authenticity, because only someone who knows the secret key could have modified the message. 
2929MACs differ from digital signatures as MAC values are both generated and verified using the same secret key. This implies that the sender and receiver of a message must agree on the same key before initiating 
2930communications, as is the case with symmetric encryption. For the same reason, MACs do not provide the property of non-repudiation offered by signatures specifically in the case of a network-wide shared 
2931secret key: any user who can verify a MAC is also capable of generating MACs for other messages.  
2932
2933
2934HMAC 
2935When using HMAC the symmetric key of the sender would be concatenated (added at the end) with the message. The result of this process (message + secret key) would be put through a hashing algorithm, and 
2936the result would be a MAC value. This MAC value is then appended to the message being sent.  If an enemy were to intercept this message and modify it, he would not have the necessary symmetric key to 
2937create a valid MAC value.  The receiver would detect the tampering because the MAC value would not be valid on the receiving side.    
2938
2939
2940
2941CBC-MAC  
2942If a CBC-MAC is being used, the message is encrypted with a symmetric block cipher in CBC mode, and the output of the final block of ciphertext is used as the MAC. The sender does not send the encrypted 
2943version of the message, but instead sends the plaintext version and the MAC attached to the message. The receiver receives the plaintext message and encrypts it with the same symmetric block cipher in CBC 
2944mode and calculates an independent MAC value. The receiver compares the new MAC value with the MAC value sent with the message. This method does not use a hashing algorithm as does HMAC. 
2945
2946
2947Cipher-Based Message Authentication Code (CMAC) 
2948Some security issues with CBC-MAC were found and they created Cipher-Based Message Authentication Code (CMAC) as a replacement. CMAC provides the same type of data origin authentication and integrity 
2949as CBC-MAC, but is more secure mathematically. CMAC is a variation of CBC-MAC. It is approved to work with AES and Triple DES. HMAC, CBC-MAC, and CMAC work higher in the network stack and can identify 
2950not only transmission errors (accidental), but also more nefarious modifications, as in an attacker messing with a message for her own benefit. This means all of these technologies can identify intentional, 
2951unauthorized modifications and accidental changes— three in one. 
2952
2953
29543C1 Vetting of proprietary cryptography 
29553C2 Computational overhead 
29563C3 Useful life 
2957LIFESPAN - The correct answer to this question is "Session Key" (SHORTEST) as session key is a symmetric key that is used to encrypt messages between two users. A session key is only good for one 
2958communication session between users. 
2959
2960
2961For example , If Tanya has a symmetric key that she uses to encrypt messages between Lance and herself all the time , then this symmetric key would not be regenerated or changed. They would use the same 
2962key every time they communicated using encryption. However , using the same key repeatedly increases the chances of the key being captured and the secure communication being compromised. If , on the 
2963other hand , a new symmetric key were generated each time Lance and Tanya wanted to communicate , it would be used only during their dialog and then destroyed. if they wanted to communicate and hour 
2964later , a new session key would be created and shared. 
2965The other answers are not correct because : 
2966Public Key can be known to anyone. 
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976Private Key must be known and used only by the owner. 
2977Secret Keys are also called as Symmetric Keys, because this type of encryption relies on each user to keep the key a secret and properly protected. 
2978
2979
29803C4 Design testable cryptographic system 
2981
2982
29833D Define key management lifecycle (e.g. creation, distribution, ecrow, recovery) 
2984
2985Key clustering happens when a plaintext message generates identical ciphertext messages using the same transformation algorithm, but with different keys. 
2986
2987
2988Internet Security Association Key Management Protocol (ISAKMP) is a key management protocol used by IPSec.  ISAKMP (Internet Security Association and Key Management Protocol) is a 
2989protocol defined by RFC 2408 for establishing Security Associations (SA) and cryptographic keys in an Internet environment. ISAKMP only provides a framework for authentication and key exchange.  The actual 
2990key exchange is done by the Oakley Key Determination Protocol which is a key-agreement protocol that allows authenticated parties to exchange keying material across an insecure connection using the Diffie- 
2991Hellman key exchange algorithm. 
2992The Internet Security Association and Key Management Protocol (ISAKMP) is a framework that defines the phases for establishing a secure relationship and support for negotiation of security attributes, it does 
2993not establish sessions keys by itself, it is used along with the Oakley session key establishment protocol.  The Secure Key Exchange Mechanism (SKEME) describes a secure exchange mechanism and Oakley 
2994defines the modes of operation needed to establish a secure connection.  
2995ISAKMP provides a framework for Internet key management and provides the specific protocol support for negotiation of security attributes. Alone, it does not establish session keys. However it can be used 
2996with various session key establishment protocols, such as Oakley, to provide a complete solution to Internet key management. 
2997
2998
2999
3000Diffie-Hellman and one variation of the Diffie-Hellman algorithm called the Key Exchange Algorithm (KEA) are also key exchange protocols.   Key exchange (also known as "key establishment") is any 
3001
3002method in cryptography by which cryptographic keys are exchanged between users, allowing use of a cryptographic algorithm.  Diffie–Hellman key exchange (D–H) is a specific method of exchanging keys. It is 
3003one of the earliest practical examples of key exchange implemented within the field of cryptography. The Diffie–Hellman key exchange method allows two parties that have no prior knowledge of each other to 
3004jointly establish a shared secret key over an insecure communications channel. This key can then be used to encrypt subsequent communications using a symmetric key cipher. It deals with discrete logarithms 
3005
3006
3007MQV (Menezes–Qu–Vanstone) is an authenticated protocol for key agreement based on the Diffie–Hellman scheme. Like other authenticated Diffie-Hellman schemes, MQV provides protection 
3008against an active attacker. The protocol can be modified to work in an arbitrary finite group, and, in particular, elliptic curve groups, where it is known as elliptic curve MQV (ECMQV).  
3009Both parties in the exchange calculate an implicit signature using its own private key and the other's public key. 
3010It uses implicit signatures. 
3011
3012
3013
3014Clipper Chip, except that keys are not escrowed by law enforcement agencies, but by specialized escrow agencies.  
3015There is nonetheless a concern with these agencies' ability to protect escrowed keys, and whether they may divulge them in unauthorized ways.  
3016
3017
3018The fact that the Skipjack algorithm (used in the Clipper Chip) was never opened for public review is a concern in the fact that it has never been publicly tested to ensure that the developers did not miss any 
3019important steps in building a complex and secure mechanism.  
3020Because the algorithm was never released for public review, many people in the public did not initially trust its effectiveness.   It was declassified on 24 June 1998 and became available for public scrutiny at that 
3021point. 
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032The Clipper Chip is a NSA designed tamperproof chip for encrypting data and it uses the SkipJack algorithm. Each Clipper Chip has a unique serial number and a copy of the unit key is stored in the database 
3033under this serial number. The sending Clipper Chip generates and sends a Law Enforcement Access Field (LEAF) value included in the transmitted message. It is based on a 80-bit key and a 16-bit checksum. 
3034
3035
30363E Design integrated cryptographic  solutions (e.g. public key infrastructure (PKI), API selection, identity system intergration) 
3037
3038
3039
3040
3041
3042
3043PKI stands for Public Key Infrastructure.  
3044
3045It supports public key exchange and it is responsible for issuing, locating, trusting, renewing, and revoking certificates. 
3046A Public Key Infrastructure (PKI) provides confidentiality, access control, integrity, authentication and non-repudiation. 
3047It does not provide reliability services. 
3048
3049
3050Public key certificate (or identity certificate) is an electronic document which incorporates a digital signature to bind together a public key with an identity — information such as the name of a 
3051person or an organization, their address, and so forth. The certificate can be used to verify that a public key belongs to an individual. 
3052
3053
3054In a typical public key infrastructure (PKI) scheme, the signature will be of a certificate authority (CA). In a web of trust scheme, the signature is of either the user (a self-signed certificate) or other users 
3055("endorsements"). In either case, the signatures on a certificate are attestations by the certificate signer that the identity information and the public key belong together. 
3056In computer security, an authorization certificate (also known as an attribute certificate) is a digital document that describes a written permission from the issuer to use a service or a resource that the issuer 
3057controls or has access to use. The permission can be delegated. 
3058Some people constantly confuse PKCs and ACs.  An analogy may make the distinction clear.  A PKC can be considered to be like a passport: it identifies the holder, tends to last for a long time, and should not be 
3059trivial to obtain.  An AC is more like an entry visa: it is typically issued by a different authority and does not last for as long a time. As acquiring an entry visa typically requires presenting a passport, getting a visa 
3060can be a simpler process. 
3061A real life example of this can be found in the mobile software deployments by large service providers and are typically applied to platforms such as Microsoft Smartphone (and related), Symbian OS, J2ME, and 
3062others. 
3063In each of these systems a mobile communications service provider may customize the mobile terminal client distribution (ie. the mobile phone operating system or application environment) to include one or 
3064more root certificates each associated with a set of capabilities or permissions such as "update firmware", "access address book", "use radio interface", and the most basic one, "install and execute". When a 
3065developer wishes to enable distribution and execution in one of these controlled environments they must acquire a certificate from an appropriate CA, typically a large commercial CA, and in the process they 
3066usually have their identity verified using out-of-band mechanisms such as a combination of phone call, validation of their legal entity through government and commercial databases, etc., similar to the high 
3067assurance SSL certificate vetting process, though often there are additional specific requirements imposed on would-be developers/publishers. 
3068Once the identity has been validated they are issued an identity certificate they can use to sign their software; generally the software signed by the developer or publisher's identity certificate is not distributed 
3069but rather it is submitted to processor to possibly test or profile the content before generating an authorization certificate which is unique to the particular software release. That certificate is then used with an 
3070ephemeral asymmetric key-pair to sign the software as the last step of preparation for distribution. There are many advantages to separating the identity and authorization certificates especially relating to risk 
3071mitigation of new content being accepted into the system and key management as well as recovery from errant software which can be used as attack vectors. 
3072
3073
3074A Certificate authority is incorrect as it is a part of PKI in which the certificate is created and signed by a trusted 3rd party. 
3075A Registration authority is incorrect as it performs the certification registration duties in PKI. 
3076A X.509 certificate is incorrect as a certificate is the mechanism used to associate a public key with a collection of components in a manner that is sufficient to uniquely identify the claimed owner. 
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088Public key infrastructure (PKI) consists of programs, data formats, procedures, communication protocols, security policies, and public key cryptographic mechanisms working in a comprehensive manner to 
3089enable a wide range of dispersed people to communicate in a secure and predictable fashion. In other words, a PKI establishes a level of trust within an environment. PKI is an ISO authentication framework that 
3090uses public key cryptography and the X.509 standard. The framework was set up to enable authentication to happen across different networks and the Internet. Particular protocols and algorithms are not 
3091specified, which is why PKI is called a framework and not a specific technology.  
3092PKI provides authentication, confidentiality, nonrepudiation, and integrity of the messages exchanged. PKI is a hybrid system of symmetric and asymmetric key algorithms and methods. 
3093PKI is made up of many different parts: certificate authorities, registration authorities, certificates, keys, and users. 
3094Each person who wants to participate in a PKI requires a digital certificate, which is a credential that contains the public key for that individual along with other identifying information. The certificate is created 
3095and signed (digital signature) by a trusted third party, which is a certificate authority (CA). When the CA signs the certificate, it binds the individual’s identity to the public key, and the CA takes liability for the 
3096authenticity of that individual. It is this trusted third party (the CA) that allows people who have never met to authenticate to each other and communicate in a secure method. If Kevin has never met David, but 
3097would like to communicate securely with him, and they both trust the same CA, then Kevin could retrieve David’s digital certificate and start the process. 
3098
3099
3100Public keys are published through digital certificates, signed by certification authority (CA), binding the certificate to the identity of its bearer. 
3101
3102
3103Revocation Request Grace Period - The length of time between the Issuer’s receipt of a revocation request and the time the Issuer is required to revoke the certificate should bear a reasonable 
3104relationship to the amount of risk the participants are willing to assume that someone may rely on a certificate for which a proper evocation request has been given but has not yet been acted upon. 
3105How quickly revocation requests need to be processed (and CRLs or certificate status databases need to be updated) depends upon the specific application for which the Policy Authority is rafting the Certificate 
3106Policy.  
3107A Policy Authority should recognise that there may be risk and lost tradeoffs with respect to grace periods for revocation notices.  
3108If the Policy Authority determines that its PKI participants are willing to accept a grace period of a few hours in exchange for a lower implementation cost, the Certificate Policy may reflect that decision.  
3109Thanks to Thomas Fung for finding a mistake in this question and providing a second reference on the subject. 
3110Thanks to Vince Martinez for reporting issues with words that were truncated. 
3111
3112
3113Digital certificate helps others verify that the public keys presented by users are genuine and valid. 
3114A digital certificate is an electronic "credit card" that establishes your credentials when doing business or other transactions on the Web.  
3115It is issued by a certification authority (CA). It contains your name, a serial number, expiration dates, a copy of the certificate holder's public key (used for encrypting messages), and the digital signature of the 
3116certificate-issuing authority so that a recipient can verify that the certificate is real. Some digital certificates conform to a standard, X.509. Digital certificates can be kept in registries so that authenticating users 
3117can look up other users' public keys.  
3118A Digital Certificate is not like same as a digital signature, they are two different things, a digital Signature is created by using your Private key to encrypt a message digest and a Digital Certificate is issued by a 
3119trusted third party who vouch for your identity. 
3120There are many other third parties which are providing Digital Certifictes and not just Verisign, RSA. 
3121In cryptography, a public key certificate (also known as a digital certificate or identity certificate) is an electronic document which uses a digital signature to bind together a public key with an identity — 
3122information such as the name of a person or an organization, their address, and so forth.  The certificate can be used to verify that a public key belongs to an individual. 
3123
3124
3125In a typical public key infrastructure (PKI) scheme, the signature will be of a certificate authority (CA).  In a web of trust scheme such as PGP or GPG, the signature is of either the user (a self-signed certificate) or 
3126other users ("endorsements") by getting people to sign each other keys.  In either case, the signatures on a certificate are attestations by the certificate signer that the identity information and the public key 
3127belong together. 
3128
3129
3130An entity that issues digital certificates (especially X.509 certificates) and vouches for the binding between the data items in a certificate.  
3131An authority trusted by one or more users to create and assign certificates.  Optionally, the certification authority may create the user's keys.  
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142X509 Certificate users depend on the validity of information provided by a certificate.  Thus, a CA should be someone that certificate users trust, and usually holds an official position created and granted power 
3143by a government, a corporation, or some other organization.  A CA is responsible for managing the life cycle of certificates and, depending on the type of certificate and the CPS that applies, may be responsible 
3144for the life cycle of key pairs associated with the certificates 
3145
3146
3147Users can obtain certificates with various levels of assurance. 
3148Class 1/Level 1 for individuals, intended for email, no proof of identityFor example, level 1 certificates verify electronic mail addresses. This is done through the use of a personal information number that a user 
3149would supply when asked to register. This level of certificate may also provide a name as well as an electronic mail address; however, it may or may not be a genuine name (i.e., it could be an alias).  This proves 
3150that a human being will reply back if you send an email to that name or email address. 
3151Class 2/Level 2 is for organizations and companies for which proof of identity is requiredLevel 2 certificates verify a user's name, address, social security number, and other information against a credit bureau 
3152database. 
3153Class 3/Level 3 is for servers and software signing, for which independent verification and checking of identity and authority is done by the issuing certificate authorityLevel 3 certificates are available to 
3154companies.  This level of certificate provides photo identification to accompany the other items of information provided by a level 2 certificate. 
3155Class 4 for online business transactions between companies 
3156Class 5 for private organizations or governmental security 
3157
3158
3159The Internet Security Glossary (RFC2828) defines an attribute certificate as a digital certificate that binds a set of descriptive data items, other than a public key, either directly to a subject name or to the 
3160identifier of another certificate that is a public-key certificate. A public-key certificate binds a subject name to a public key value, along with information needed to perform certain cryptographic functions. Other 
3161attributes of a subject, such as a security clearance, may be certified in a separate kind of digital certificate, called an attribute certificate. A subject may have multiple attribute certificates associated with its 
3162name or with each of its public-key certificates. 
3163
3164
3165
3166
3167
3168CRL 
3169Certificate revocation is the process of revoking a certificate before it expires.  
3170A certificate may need to be revoked because it was stolen, an employee moved to a new company, or someone has had their access revoked. A certificate revocation is handled either through a Certificate 
3171Revocation List (CRL) or by using the Online Certificate Status Protocol (OCSP).  
3172A repository is simply a database or database server where the certificates are stored. The process of revoking a certificate begins when the CA is notified that a particular certificate needs to be revoked. This 
3173must be done whenever the private key becomes known/compromised.  
3174The owner of a certificate can request it be revoked at any time, or the request can be made by the administrator. The CA marks the certificate as revoked. This information is published in the CRL. The 
3175revocation process is usually very quick; time is based on the publication interval for the CRL.  
3176Disseminating the revocation information to users may take longer. Once the certificate has been revoked, it can never be used—or trusted—again. The CA publishes the CRL on a regular basis, usually either 
3177hourly or daily. The CA sends or publishes this list to organizations that have chosen to receive it; the publishing process occurs automatically in the case of PKI. The time between when the CRL is issued and 
3178when it reaches users may be too long for some applications. This time gap is referred to as latency.  
3179OCSP solves the latency problem: If the recipient or relaying party uses OCSP for verification, the answer is available immediately. 
3180
3181
3182ARL - The Internet Security Glossary (RFC2828) defines the Authority Revocation List (ARL) as a data structure that enumerates digital certificates that were issued to CAs but have been invalidated by their 
3183issuer prior to when they were scheduled to expire.  
3184Do not to confuse with an ARL with a Certificate Revocation List (CRL). A certificate revocation list is a mechanism for distributing notices of certificate revocations. 
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197Registration Authority (RA) A registration authority (RA) is an authority in a network that verifies user requests for a digital certificate and tells the certificate authority (CA) to issue it. RAs are part of a 
3198public key infrastructure (PKI), a networked system that enables companies and users to exchange information and money safely and securely. The digital certificate contains a public key that is used to encrypt 
3199and decrypt messages and digital signatures. 
3200
3201
3202Recovery agent  Sometimes it is necessary to recover a lost key. One of the problems that often arises regarding PKI is the fear that documents will become lost forever—irrecoverable because someone 
3203loses or forgets his private key. Let’s say that employees use Smart Cards to hold their private keys. If a user was to leave his Smart Card in his or her wallet that was left in the pants that he or she accidentally 
3204threw into the washing machine, then that user might be without his private key and therefore incapable of accessing any documents or e-mails that used his existing private key. 
3205Many corporate environments implement a key recovery server solely for the purpose of backing up and recovering keys. Within an organization, there typically is at least one key recovery agent. A key recovery 
3206agent has the authority and capability to restore a user’s lost private key. Some key recovery servers require that two key recovery agents retrieve private user keys together for added security. This is similar to 
3207certain bank accounts, which require two signatures on a check for added security. Some key recovery servers also have the ability to function as a key escrow server, thereby adding the ability to split the keys 
3208onto two separate recovery servers, further increasing security. 
3209
3210
3211Key escrow (also known as a “fair” cryptosystem) is an arrangement in which the keys needed to decrypt encrypted data are held in escrow so that, under certain circumstances, an authorized third party may 
3212gain access to those keys. These third parties may include businesses, who may want access to employees' private communications, or governments, who may wish to be able to view the contents of encrypted 
3213communications. 
3214
3215
3216
3217
3218
3219---------------------------------- 
3220
3221OTHER 
3222
3223
3224The Internet Key Exchange (IKE) protocol is a key management protocol standard that is used in conjunction with the IPSec standard. IKE enhances IPSec by providing additional features, flexibility, and 
3225ease of configuration for the IPSec standard. IPSec can however, be configured without IKE by manually configuring the gateways communicating with each other for example.  
3226A security association (SA) is a relationship between two or more entities that describes how the entities will use security services to communicate securely. 
3227In phase 1 of this process, IKE creates an authenticated, secure channel between the two IKE peers, called the IKE security association. The Diffie-Hellman key agreement is always performed in this phase. 
3228In phase 2 IKE negotiates the IPSec security associations and generates the required key material for IPSec. The sender offers one or more transform sets that are used to specify an allowed combination of 
3229transforms with their respective settings. 
3230Benefits provided by IKE include:  
3231    •    Eliminates the need to manually specify all the IPSec security parameters in the crypto maps at both peers.  
3232    •    Allows you to specify a lifetime for the IPSec security association.  
3233    •    Allows encryption keys to change during IPSec sessions.  
3234    •    Allows IPSec to provide anti-replay services.  
3235    •    Permits Certification Authority (CA) support for a manageable, scalable IPSec implementation.  
3236    •    Allows dynamic authentication of peers. 
3237RFC 2828 (Internet Security Glossary) defines IKE as an Internet, IPsec, key-establishment protocol (partly based on OAKLEY) that is intended for putting in place authenticated keying material for use with 
3238ISAKMP and for other security associations, such as in AH and ESP. 
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250IKE does not need a Public Key Infrastructure (PKI) to work. Internet Key Exchange (IKE or IKEv2) is the protocol used to set up a security association (SA) in the IPsec protocol suite. IKE builds upon the Oakley 
3251protocol and ISAKMP. IKE uses X.509 certificates for authentication which are either pre-shared or distributed using DNS (preferably with DNSSEC) and a Diffie–Hellman key exchange to set up a shared session 
3252secret from which cryptographic keys are derived. 
3253
3254
3255OAKLEY - RFC 2828 (Internet Security Glossary) defines OAKLEY as a key establishment protocol (proposed for IPsec but superseded by IKE) based on the Diffie-Hellman algorithm and designed to be a 
3256compatible component of ISAKMP. 
3257ISAKMP is an Internet IPsec protocol to negotiate, establish, modify, and delete security associations, and to exchange key generation and authentication data, independent of the details of any specific key 
3258generation technique, key establishment protocol, encryption algorithm, or authentication mechanism. 
3259The Oakley protocol uses a hybrid Diffie-Hellman technique to establish session keys on Internet hosts and routers. Oakley provides the important security property of Perfect Forward Secrecy (PFS) and is based 
3260on cryptographic techniques that have survived substantial public scrutiny. Oakley can be used by itself, if no attribute negotiation is needed, or Oakley can be used in conjunction with ISAKMP. When ISAKMP is 
3261used with Oakley, key escrow is not feasible. 
3262The ISAKMP and Oakley protocols have been combined into a hybrid protocol. The resolution of ISAKMP with Oakley uses the framework of ISAKMP to support a subset of Oakley key exchange modes. This new 
3263key exchange protocol provides optional PFS, full security association attribute negotiation, and authentication methods that provide both repudiation and non-repudiation. Implementations of this protocol can 
3264be used to establish VPNs and also allow for users from remote sites (who may have a dynamically allocated IP address) access to a secure network. 
3265
3266
3267SKEME describes a versatile key exchange technique which provides anonymity, repudiability, and quick key refreshment. SKEME constitutes a compact protocol that supports a variety of realistic scenarios 
3268and security models over Internet. It provides clear tradeoffs between security and performance as required by the different scenarios without incurring in unnecessary system complexity. The protocol supports 
3269key exchange based on public key, key distribution centers, or manual installation, and provides for fast and secure key refreshment. In addition, SKEME selectively provides perfect forward secrecy, allows for 
3270replaceability and negotiation of the underlying cryptographic primitives, and addresses privacy issues as anonymity and repudiatability  
3271SKEME's basic mode is based on the use of public keys and a Diffie-Hellman shared secret generation.  
3272However, SKEME is not restricted to the use of public keys, but also allows the use of a pre-shared key. This key can be obtained by manual distribution or by the intermediary of a key distribution center (KDC) 
3273such as Kerberos.  
3274In short, SKEME contains four distinct modes:  
3275Basic mode, which provides a key exchange based on public keys and ensures PFS thanks to Diffie-Hellman. A key exchange based on the use of public keys, but without Diffie-Hellman. A key exchange based on 
3276the use of a pre-shared key and on Diffie-Hellman. A mechanism of fast rekeying based only on symmetrical algorithms. In addition, SKEME is composed of three phases: SHARE, EXCH and AUTH.  
3277During the SHARE phase, the peers exchange half-keys, encrypted with their respective public keys. These two half-keys are used to compute a secret key K. If anonymity is wanted, the identities of the two 
3278peers are also encrypted. If a shared secret already exists, this phase is skipped.  
3279The exchange phase (EXCH) is used, depending on the selected mode, to exchange either Diffie-Hellman public values or nonces. The Diffie-Hellman shared secret will only be computed after the end of the 
3280exchanges.  
3281The public values or nonces are authenticated during the authentication phase (AUTH), using the secret key established during the SHARE phase. 
3282
3283
3284SKIP is a key distribution protocol that uses hybrid encryption to convey session keys that are used to encrypt data in IP packets. RFC 2828 (Internet Security Glossary) defines Simple Key Management for 
3285Internet Protocols (SKIP) as: 
3286A key distribution protocol that uses hybrid encryption to convey session keys that are used to encrypt data in IP packets. 
3287SKIP is an hybrid Key distribution protocol similar to SSL, except that it establishes a long-term key once, and then requires no prior communication in order to establish or exchange keys on a session-by-session 
3288basis. Therefore, no connection setup overhead exists and new keys values are not continually generated. SKIP uses the knowledge of its own secret key or private component and the destination's public 
3289component to calculate a unique key that can only be used between them. 
3290
3291
3292The Key Exchange Algorithm (KEA) is defined as a key agreement algorithm that is similar to the Diffie-Hellman algorithm, uses 1024-bit asymmetric keys, and was developed and formerly classified 
3293at the secret level by the NSA. 
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305FIPS-140 - Hardware and software cryptographic modules 
3306
3307
3308SSL - The Secure Socket Layer (SSL) and also the Transport Layer Security (TLS) protocols are used for the encryption of Hypertext Transport Protocol (HTTP) data between a Web Browser and a Web 
3309Server. 
3310SSL/TLS and The Internet Protocol Security (IPSec) protocol suite both provides a method of setting up a secure channel for protecting data exchange between two entities wishing to communicate securely with 
3311each other. 
3312The biggest difference between IPSEC and SSL is: 
3313Using IPSEC the encryption is done at the Network Layer of the OSI model.  The IPSEC devices that share this secure channel can be two servers, two routers, a workstation and a server, or two gateways 
3314between different networks.  It is always from a HOST to another HOST.  
3315SSL/TLS is used for APPLICATION to APPLICATION secure channels.   The question was making reference specifically to a Web Browser,  being an Application this ruled out IPSEC as a valid choice. 
3316For the purpose of the exam you must understand these differences. 
3317SSL provides security services at the Transport Layer of the OSI model. 
3318SSL 3.0 (Secure Socket Layer) and TLS 1.1 (Transport Layer Security) are essentially fully compatible, with SSL being a session encryption tool originally developed by Netscape and TLS 1.1 being 
3319the open standard IETF version of SSL 3.0. 
3320
3321
3322SSL is one of the most common protocols used to protect Internet traffic. It encrypts the messages using symmetric algorithms, such as IDEA, DES, 3DES, and Fortezza, and also calculates the MAC (Message 
3323Authentication Code) for the message using MD5 or SHA-1.   
3324The MAC is appended to the message and encrypted along with the message data. The exchange of the symmetric keys is accomplished through various versions of Diffie–Hellmann or RSA.  TLS is the Internet 
3325standard based on SSLv3.  TLSv1 is backward compatible with SSLv3.  It uses the same algorithms as SSLv3; however, it computes an HMAC instead of a MAC along with other enhancements to improve security. 
3326Transport The protocols at the transport layer handle end-to-end transmission and segmentation of a data stream. The following protocols work at this layer: • Transmission Control Protocol (TCP) • User 
3327Datagram Protocol (UDP) • Secure Sockets Layer (SSL)/ Transport Layer Security (TLS) • Sequenced Packet Exchange (SPX). 
3328
3329
3330Once the merchant server has been authenticated by the browser client, the browser generates a master secret that is to be shared only between the server and client. This secret serves as a seed to 
3331generate the session (private) keys. The master secret is then encrypted with the merchant's public key and sent to the server. The fact that the master secret is generated by the client's browser provides the 
3332client assurance that the server is not reusing keys that would have been used in a previous session with another client. 
3333
3334
3335Cryptology is the science that includes both cryptography and cryptanalysis and is not directly concerned with key management.  Cryptology is the mathematics, such as number theory, and the 
3336application of formulas and algorithms, that underpin cryptography and cryptanalysis. 
3337
3338
3339The Secure Electronic Transaction (SET) was developed by a consortium including MasterCard and VISA as a means of preventing fraud from occurring during electronic payment. 
3340
3341
3342Kerberos depends on Secret Keys or Symmetric Key cryptography. 
3343Kerberos a third party authentication protocol. It was designed and developed in the mid 1980's by MIT. It is considered open source but is copyrighted and owned by MIT. It relies on the user's secret keys.  The 
3344password is used to encrypt and decrypt the keys.  
3345This question asked specifically about encryption methods.   Encryption methods can be SYMMETRIC (or secret key)  in which encryption and decryption keys are the same, or ASYMMETRIC (aka 'Public Key') in 
3346which encryption and decryption keys differ.  
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357'Public Key' methods must be asymmetric, to the extent that the decryption key CANNOT be easily derived from the encryption key.  Symmetric keys, however, usually encrypt more efficiently, so they lend 
3358themselves to encrypting large amounts of data.  Asymmetric encryption is often limited to ONLY encrypting a symmetric key and other information that is needed in order to decrypt a data stream, and the 
3359remainder of the encrypted data uses the symmetric key method for performance reasons. This does not in any way diminish the security nor the ability to use a public key to encrypt the data, since the 
3360symmetric key method is likely to be even MORE secure than the asymmetric method. 
3361For symmetric key ciphers, there are basically two types: BLOCK CIPHERS, in which a fixed length block is encrypted, and STREAM CIPHERS, in which the data is encrypted one 'data unit' (typically 1 byte) at a 
3362time, in the same order it was received in. 
3363
3364
3365
3366IPSEC 
3367
3368The IETF's IPSec Working Group  develops standards for IP-layer security mechanisms for both IPv4 and IPv6. The group also is developing generic key management protocols for use on the Internet. For more 
3369information, refer to the IP Security and Encryption Overview.  
3370IPSec is a framework of open standards developed by the Internet Engineering Task Force (IETF) that provides security for transmission of sensitive information over unprotected networks such as the Internet. It 
3371acts at the network level and implements the following standards:  
3372•IPSec  
3373•Internet Key Exchange (IKE)  
3374•Data Encryption Standard (DES)  
3375•MD5 (HMAC variant)  
3376•SHA (HMAC variant)  
3377•Authentication Header (AH)  
3378•Encapsulating Security Payload (ESP)  
3379IPSec services provide a robust security solution that is standards-based. IPSec also provides data authentication and anti-replay services in addition to data confidentiality services.  
3380
3381
3382Why even bother with AH then?  
3383In most cases, the reason has to do with whether the environment is using network address translation (NAT). IPSec will generate an integrity check value (ICV), which is really the same thing as a MAC value, 
3384over a portion of the packet. Remember that the sender and receiver generate their own values. In IPSec, it is called an ICV value. The receiver compares her ICV value with the one sent by the sender. If the 
3385values match, the receiver can be assured the packet has not been modified during transmission. If the values are different, the packet has been altered and the receiver discards the packet. 
3386The AH protocol calculates this ICV over the data payload, transport, and network headers. If the packet then goes through a NAT device, the NAT device changes the IP address of the packet. That is its job. This 
3387means a portion of the data (network header) that was included to calculate the ICV value has now changed, and the receiver will generate an ICV value that is different from the one sent with the packet, which 
3388means the packet will be discarded automatically. 
3389The ESP protocol follows similar steps, except it does not include the network header portion when calculating its ICV value. When the NAT device changes the IP address, it will not affect the receiver’s ICV value 
3390because it does not include the network header when calculating the ICV. 
3391
3392
3393Here is a tutorial on IPSEC from the Shon Harris Blog: 
3394The Internet Protocol Security (IPSec) protocol suite provides a method of setting up a secure channel for protected data exchange between two devices. The devices that share this secure channel can be two 
3395servers, two routers, a workstation and a server, or two gateways between different networks. IPSec is a widely accepted standard for providing network layer protection. It can be more flexible and less 
3396expensive than end-to end and link encryption methods. 
3397IPSec has strong encryption and authentication methods, and although it can be used to enable tunneled communication between two computers, it is usually employed to establish virtual private networks 
3398(VPNs) among networks across the Internet. 
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411IPSec is not a strict protocol that dictates the type of algorithm, keys, and authentication method to use. Rather, it is an open, modular framework that provides a lot of flexibility for companies when they 
3412choose to use this type of technology. IPSec uses two basic security protocols: Authentication Header (AH) and Encapsulating Security Payload (ESP). AH is the authenticating protocol, and ESP is an 
3413authenticating and encrypting protocol that uses cryptographic mechanisms to provide source authentication, confidentiality, and message integrity. 
3414IPSec can work in one of two modes: transport mode, in which the payload of the message is protected, and tunnel mode, in which the payload and the routing and header information are protected. ESP in 
3415transport mode encrypts the actual message information so it cannot be sniffed and uncovered by an unauthorized entity. Tunnel mode provides a higher level of protection by also protecting the header and 
3416trailer data an attacker may find useful. Figure 8-26 shows the high-level view of the steps of setting up an IPSec connection. 
3417Each device will have at least one security association (SA) for each VPN it uses. The SA, which is critical to the IPSec architecture, is a record of the configurations the device needs to support an IPSec 
3418connection. When two devices complete their handshaking process, which means they have agreed upon a long list of parameters they will use to communicate, these data must be recorded and stored 
3419somewhere, which is in the SA. 
3420The SA can contain the authentication and encryption keys, the agreed-upon algorithms, the key lifetime, and the source IP address. When a device receives a packet via the IPSec protocol, it is the SA that tells 
3421the device what to do with the packet. So if device B receives a packet from device C via IPSec, device B will look to the corresponding SA to tell it how to decrypt the packet, how to properly authenticate the 
3422source of the packet, which key to use, and how to reply to the message if necessary. 
3423SAs are directional, so a device will have one SA for outbound traffic and a different SA for inbound traffic for each individual communication channel. If a device is connecting to three devices, it will have at least 
3424six SAs, one for each inbound and outbound connection per remote device. So how can a device keep all of these SAs organized and ensure that the right SA is invoked for the right connection? With the mighty 
3425secu rity parameter index (SPI), that’s how. Each device has an SPI that keeps track of the different SAs and tells the device which one is appropriate to invoke for the different packets it receives. The SPI value is 
3426in the header of an IPSec packet, and the device reads this value to tell it which SA to consult. 
3427IPSec can authenticate the sending devices of the packet by using MAC (covered in the earlier section, “The One-Way Hash”). The ESP protocol can provide authentication, integrity, and confidentiality if the 
3428devices are configured for this type of functionality. 
3429So if a company just needs to make sure it knows the source of the sender and must be assured of the integrity of the packets, it would choose to use AH. If the company would like to use these services and also 
3430have confidentiality, it would use the ESP protocol because it provides encryption functionality. In most cases, the reason ESP is employed is because the company must set up a secure VPN connection. 
3431It may seem odd to have two different protocols that provide overlapping functionality. AH provides authentication and integrity, and ESP can provide those two functions and confidentiality. Why even bother 
3432with AH then? In most cases, the reason has to do with whether the environment is using network address translation (NAT). IPSec will generate an integrity check value (ICV), which is really the same thing as a 
3433MAC value, over a portion of the packet. Remember that the sender and receiver generate their own values. In IPSec, it is called an ICV value. The receiver compares her ICV value with the one sent by the 
3434sender. If the values match, the receiver can be assured the packet has not been modified during transmission. If the values are different, the packet has been altered and the receiver discards the packet. 
3435The AH protocol calculates this ICV over the data payload, transport, and network headers. If the packet then goes through a NAT device, the NAT device changes the IP address of the packet. That is its job. This 
3436means a portion of the data (network header) that was included to calculate the ICV value has now changed, and the receiver will generate an ICV value that is different from the one sent with the packet, which 
3437means the packet will be discarded automatically. 
3438The ESP protocol follows similar steps, except it does not include the network header portion when calculating its ICV value. When the NAT device changes the IP address, it will not affect the receiver’s ICV value 
3439because it does not include the network header when calculating the ICV. 
3440Because IPSec is a framework, it does not dictate which hashing and encryption algorithms are to be used or how keys are to be exchanged between devices. Key management can be handled manually or 
3441automated by a key management protocol. The de facto standard for IPSec is to use Internet Key Exchange (IKE), which is a combination of the ISAKMP and OAKLEY protocols. The Internet Security Association 
3442and Key Management Protocol (ISAKMP) is a key exchange architecture that is independent of the type of keying mechanisms used. Basically, ISAKMP provides the framework of what can be negotiated to set 
3443up an IPSec connection (algorithms, protocols, modes, keys). The OAKLEY protocol is the one that carries out the negotiation process. You can think of ISAKMP as providing the playing field (the infrastructure) 
3444and OAKLEY as the guy running up and down the playing field (carrying out the steps of the negotiation). 
3445IPSec is very complex with all of its components and possible configurations. This complexity is what provides for a great degree of flexibility, because a company has many different configuration choices to 
3446achieve just the right level of protection. If this is all new to you and still confusing, please review one or more of the following references to help fill in the gray areas. 
3447
3448
3449
3450
3451Pre Shared Keys 
3452In cryptography, a pre-shared key or PSK is a shared secret which was previously shared between the two parties using some secure channel before it needs to be used. To build a key from shared secret, the key derivation function 
3453should be used. Such systems almost always use symmetric key cryptographic algorithms. The term PSK is used in WiFi encryption such as WEP or WPA, where both the wireless access points (AP) and all clients share the same key. 
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463The characteristics of this secret or key are determined by the system which uses it; some system designs require that such keys be in a particular format. It can be a password like 'bret13i', a passphrase like 'Idaho hung gear id gene', or a 
3464hexadecimal string like '65E4 E556 8622 EEE1'. The secret is used by all systems involved in the cryptographic processes used to secure the traffic between the systems. 
3465
3466
3467Certificate Based Authentication 
3468The most common form of trusted authentication between parties in the wide world of Web commerce is the exchange of certificates. A certificate is a digital document that at a minimum includes a Distinguished Name (DN) and an 
3469associated public key.  
3470The certificate is digitally signed by a trusted third party known as the Certificate Authority (CA). The CA vouches for the authenticity of the certificate holder.  Each principal in the transaction presents certificate as its credentials.  The 
3471recipient then validates the certificate’s signature against its cache of known and trusted CA certificates. A “personal 
3472certificate” identifies an end user in a transaction; a “server certificate” identifies the service provider. 
3473Generally, certificate formats follow the X.509 Version 3 standard. X.509 is part of the Open Systems Interconnect 
3474X.509 is used in digital certificates. X.400 is used in e-mail as a message handling protocol. X.25 is a standard for the network and data link levels of a communication network and X.75 is a standard defining ways of 
3475connecting two X.25 networks. 
3476
3477
3478Public Key Authentication  
3479Public key authentication is an alternative means of identifying yourself to a login server, instead of typing a password. It is more secure and more flexible, but more difficult to set up.  
3480In conventional password authentication, you prove you are who you claim to be by proving that you know the correct password. The only way to prove you know the password is to tell the server what you think the password is. This 
3481means that if the server has been hacked, or spoofed an attacker can learn your password.  
3482Public key authentication solves this problem. You generate a key pair, consisting of a public key (which everybody is allowed to know) and a private key (which you keep secret and do not give to anybody). The private key is able to 
3483generate signatures. A signature created using your private key cannot be forged by anybody who does not have a copy of that private key; but anybody who has your public key can verify that a particular signature is genuine.  
3484
3485
3486So you generate a key pair on your own computer, and you copy the public key to the server. Then, when the server asks you to prove who you are, you can generate a signature using your private key. The server can verify that signature 
3487(since it has your public key) and allow you to log in. Now if the server is hacked or spoofed, the attacker does not gain your private key or password; they only gain one signature. And signatures cannot be re-used, so they have gained 
3488nothing.  
3489There is a problem with this: if your private key is stored unprotected on your own computer, then anybody who gains access to your computer will be able to generate signatures as if they were you. So they will be able to log in to your 
3490server under your account. For this reason, your private key is usually encrypted when it is stored on your local machine, using a passphrase of your choice. In order to generate a signature, you must decrypt the key, so you have to type 
3491your passphrase. 
3492
3493
3494
3495SPLIT KNOWLEDGE 
3496Split knowledge involves encryption keys being separated into two components, each of which does not reveal the other.  Split knowledge is the other complementary access control principle to dual control.  
3497In cryptographic terms, one could say dual control and split knowledge are properly implemented if no one person has access to or knowledge of the content of the complete cryptographic key being protected by the two rocesses. 
3498The sound implementation of dual control and split knowledge in a cryptographic environment necessarily means that the quickest way to break the key would be through the best attack known for the algorithm of that key. The 
3499principles of dual control and split knowledge primarily apply to access to plaintext keys.  
3500Access to cryptographic keys used for encrypting and decrypting data or access to keys that are encrypted under a master key (which may or may not be maintained under dual control and split knowledge) do not require dual control and 
3501split knowledge. Dual control and split knowledge can be summed up as the determination of any part of a key being protected must require the collusion between two or more persons with each supplying unique cryptographic 
3502materials that must be joined together to access the protected key. 
3503Any feasible method to violate the axiom means that the principles of dual control and split knowledge are not being upheld. 
3504Split knowledge is the unique “what each must bring” and joined together when implementing dual control. To illustrate, a box containing petty cash is secured by one combination lock and one keyed lock. One employee is given the 
3505combination to the combo lock and another employee has possession of the correct key to the keyed lock. 
3506In order to get the cash out of the box both employees must be present at the cash box at the same time. One cannot open the box without the other. This is the aspect of dual control.  
3507On the other hand, split knowledge is exemplified here by the different objects (the combination to the combo lock and the correct physical key), both of which are unique and necessary, that each brings to the meeting. Split knowledge 
3508focuses on the uniqueness of separate objects that must be joined together.  
3509
3510
3511Dual control has to do with forcing the collusion of at least two or more persons to combine their split knowledge to gain access to an asset. Both split knowledge and dual control complement each other and are necessary functions that 
3512implement the segregation of duties in high integrity cryptographic environments.  
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523Dual control is a procedure that uses two or more entities (usually persons) operating in concert to protect a system resource, such that no single entity acting alone can access that resource.  Dual control is implemented as a security 
3524procedure that requires two or more persons to come together and collude to complete a process. In a cryptographic system the two (or more) persons would each supply a unique key, that when taken together, performs a 
3525cryptographic process. Split knowledge is the other complementary access control principle to dual control. 
3526
3527
3528
3529PPTP - PPTP is an encapsulation protocol based on PPP that works at OSI layer 2 (Data Link) and that enables a single point-to-point connection, usually between a client and a server. While PPTP depends on IP to establish its 
3530connection.  
3531As currently implemented, PPTP encapsulates PPP packets using a modified version of the generic routing encapsulation (GRE) protocol, which gives PPTP to the flexibility of handling protocols other than IP, such as IPX and NETBEUI over 
3532IP networks. 
3533PPTP does have some limitations: 
3534It does not provide strong encryption for protecting data, nor does it support any token-based methods for authenticating users.  
3535L2TP is derived from L2F and PPTP, not the opposite. 
3536Thanks to Remigio Armano for providing feedback to improve the quality of this question. 
3537Thanks to John Baker for finding two good answer to this question. 
3538
3539
3540
3541L2F (Layer 2 Forwarding) provides no authentication or encryption.  It is a Protocol that supports the creation of secure virtual private dial-up networks over the Internet.  
3542At one point L2F was merged with PPTP to produce L2TP to be used on networks and not only on dial up links.  
3543IPSec is now considered the best VPN solution for IP environments. 
3544
3545
3546
3547LDAP vs CA Based PKI  
3548The primary security concerns relative to LDAP servers are availability and integrity.   
3549For example, denial of service attacks on an LDAP server could prevent access to the Certificate Revocation List and, thus, permit the use of a revoked certificate.   
3550Below you have a small extract comparing LDAP Based PKI versus CA Based PKI comparing benefits and disadvantages.  
3551When you compare / contrast the use of LDAP vs CA based PKI, you will find that: 
3552LDAP is used as a general directory, retaining all kinds of information. For example, a large company may use LDAP to store: 
3553  - First, middle, and last name 
3554  - Office location including address and phone number 
3555  - Electronic addresses including email, web pages and so on 
3556  - Authentication information such as user name, password, key informationand so on. 
3557CA based PKI is primarily to establish a trust relationship between two people, two companies, or an individual with a company. For xample, when I go to a secure web site such as  https://answers.google.com/answers/myquestions 
3558to check for questions I have asked, I get an assurance from my browser that the link established between my computer and Google's is secure and that Google is indeed the company I have contacted. 
3559With regard to issuing, storing, sending, retrieving certificates, let's start with the fact that an LDAP server is set up by the company or organization that is responsible for it. There is no specific requirement for an external agency (or 
3560company) such as a Certificate Authority be involved in the set up of an LDAP server. As a result of this, the following will summarize and contrast for each item: 
3561To issue a certificate in LDAP anyone with authorization to update that part of the server at the issuing company can generate it.  For a CA-PKI, there are recognized companies (the Certification Authority) that will issue the certificate for 
3562the company to use. In the latter case, the CA will also make available information to clients to verify that the certificate they receive is valid. 
3563At this point with LDAP, the certificate information is stored on the LDAP server (along with the other information stored). It may also be delivered to other systems requiring that information. In CA-PKI, you have two parts: 
3564 - the first part goes to the company / person registered with the CA 
3565 - the second part goes to the client (or perhaps better, the client application) 
3566so the two people / companies can establish the trust relationship. 
3567With LDAP, there is a defined method to request the information. As an example, let's use an LDAP server to store user names / passwords for a group of workstation. The workstation will request the username and password, encode the 
3568password, and compare it to the value fetched from the LDAP server. If they match, the user is authenticated. 
3569With CA-PKI, and you go to a secure web site (as an example), part of the setup of the connection will be an exchange of trust information.  The two parts of the information distributed / stored above are used to help establish a secure 
3570connection and provide information that the user can use to verify everything is OK. For example, when I connect to my bank using a secure web browser, I can pull up a description of the certificate indicating: 
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581 - the name of the company I am dealing with 
3582 - the name of the Certification Authority 
3583 - the range of dates the certificate is valid 
3584as well as a variety of other information that experts could use to verify the certificate (the application already said its OK). 
3585What are the advantages / disadvantages? 
3586This was answered in part above based on the different types of application domains. In terms of security, LDAP is only as secure as the server on which the information is stored. For many purposes, the LDAP server is the  authoritative 
3587basis of the information (as above - the user authentication). This also works best when the access to the network is controlled so you can prevent "man in the middle" attacks and similar problems. 
3588In CA-PKI systems, the security comes from  
3589 - an independent company / organization that identifies the company / person that will receive the certificate 
3590 - independent distribution of public key information (the private part at the company, the public part in each client application) 
3591 - strong encryption methods used to validate the identify of both systems this works on both secure networks as insecure ones (such as the Internet). 
3592
3593
3594
3595Pretty Good Privacy (PGP) was designed by Phil Zimmerman as a freeware e-mail security program and was released in 1991. It was the first widespread public key encryption program.  PGP is a complete cryptosystem that 
3596
3597uses cryptographic protection to protect e-mail and files.  It can use RSA public key encryption for key management and use IDEA symmetric cipher for bulk encryption of data,  although the user has the option of picking different 
3598types of algorithms for these functions.  PGP can provide confidentiality by using the IDEA encryption algorithm, integrity by using the MD5 hashing algorithm, authentication by using the public key certificates, and nonrepudiation by 
3599using cryptographically signed messages.  PGP initially used its own type of digital certificates rather than what is used in PKI, but they both have similar purposes.   Today PGP support X.509 V3 digital certificates.  
3600Notice that the question specifically asks what PGP uses to encrypt  For this, PGP uses an symmetric key algorithm. PGP then uses an asymmetric key algorithm to encrypt the session key and then send it securely to the receiver. It is an 
3601hybrid system where both types of ciphers are being used for different purposes.  
3602Whenever a question talks about the bulk of the data to be sent, Symmetric is always best to choice to use because of the inherent speed within Symmetric Ciphers.   Asymmetric ciphers are 100 to 1000 times slower than 
3603Symmetric Ciphers. 
3604
3605
3606
3607The OCSP - (Online Certificate Status Protocol) provides real-time certificate checks and a Certificate Revocation List (CRL) has a delay in the updates. In lieu of or as a supplement to checking against a periodic CRL, it may be 
3608necessary to obtain timely information regarding the revocation status of a certificate (cf. [RFC2459], Section 3.3). Examples include high-value funds transfer or large stock trades. 
3609
3610
3611The Online Certificate Status Protocol (OCSP) enables applications to determine the (revocation) state of an identified certificate. OCSP may be used to satisfy some of the operational requirements of providing more timely revocation 
3612information than is possible with CRLs and may also be used to obtain additional status information. An OCSP client issues a status request to an OCSP responder and suspends acceptance of the certificate in question until the responder 
3613provides a response. 
3614This protocol specifies the data that needs to be exchanged between an application checking the status of a certificate and the server providing that status. 
3615
3616
3617SMIME - Content security measures presumes that the content is available in cleartext on the central mail server.  
3618Encrypted emails have to be decrypted before it can be filtered (e.g. to detect viruses), so you need the decryption key on the central "crypto mail server".  
3619There are several ways for such key management, e.g. by message or key recovery methods. However, that would certainly require further processing in order to achieve such goal. It is Public key based, hybrid encryption scheme. 
3620
3621
3622LINK Encryption and END-TO-END ENCRYPTION 
3623In link encryption, each entity has keys in common with its two neighboring nodes in the transmission chain.  
3624Thus, a node receives the encrypted message from its predecessor, decrypts it, and then re-encrypts it with a new key, common to the successor node. Obviously, this mode does not provide protection if anyone of the nodes along the 
3625transmission path is compromised. 
3626Encryption can be performed at different communication levels, each with different types of protection and implications. Two general modes of encryption implementation are link encryption and end-to-end encryption. 
3627Link encryption encrypts all the data along a specific communication path, as in a satellite link, T3 line, or telephone circuit. Not only is the user information encrypted, but the header, trailers, addresses, and routing data that are part of 
3628the packets are also encrypted. The only traffic not encrypted in this technology is the data link control messaging information, which includes instructions and parameters that the different link devices use to synchronize communication 
3629methods. Link encryption provides protection against packet sniffers and eavesdroppers.  
3630In end-to-end encryption, the headers, addresses, routing, and trailer information are not encrypted, enabling attackers to learn more about a captured packet and where it is headed. 
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642When using link encryption, packets have to be decrypted at each hop and encrypted again. Information staying encrypted from one end of its journey to the other is a characteristic of end-to-end encryption, not link 
3643encryption. 
3644Link Encryption vs. End-to-End EncryptionLink encryption encrypts the entire packet, including headers and trailers, and has to be decrypted at each hop. End-to-end encryption does not encrypt the headers and trailers, and therefore 
3645does not need to be decrypted at each hop.Reference: All in one 4th Edition, Page 735 & Glossary 
3646
3647
3648WTLS 
3649Wireless Transport Layer Security (WTLS) is a communication protocol that allows wireless devices to send and receive encrypted information over the Internet. S-WAP is not defined. WSP (Wireless Session Protocol) and WDP (Wireless 
3650Datagram Protocol) are part of Wireless Access Protocol (WAP). 
3651
3652
3653
3654Key recovery as a process for learning the value of a cryptographic key that was previously used to perform some cryptographic operation.  
3655Key encapsulation is one class of key recovery techniques and is defined as a key recovery technique for storing knowledge of a cryptographic key by encrypting it with another key and ensuring that that only certain third parties called 
3656"recovery agents" can perform the decryption operation to retrieve the stored key.  Key encapsulation typically allows direct retrieval of the secret key used to provide data confidentiality.  
3657The other class of key recovery technique is Key escrow, defined as a technique for storing knowledge of a cryptographic key or parts thereof in the custody of one or more third parties called "escrow agents", so that the key can be 
3658recovered and used in specified circumstances. 
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
37084.A Identify security architecture approach 
37094.A.1 Types and scope (e.g. enterprise, network, SOA) 
37104.A.2 Frameworks 
3711Sherwood Applied Business Security Architecture - SABSA  
3712SABSA is a model and a methodology for developing risk-driven enterprise information security architectures and for delivering security infrastructure solutions that 
3713support critical business initiatives. The primary characteristic of the SABSA model is that everything must be derived from an analysis of the business requirements for 
3714security, especially those in which security has an enabling function through which new business opportunities can be developed and exploited. 
3715The process analyzes the business requirements at the outset, and creates a chain of traceability through the strategy and concept, design, implementation, and ongoing 
3716‘manage and measure’ phases of the lifecycle to ensure that the business mandate is preserved. Framework tools created from practical experience further support the 
3717whole methodology. 
3718The model is layered, with the top layer being the business requirements definition stage. At each lower layer a new level of abstraction and detail is developed, going 
3719through the definition of the conceptual architecture, logical services architecture, physical infrastructure architecture and finally at the lowest layer, the selection of 
3720technologies and products (component architecture). 
3721The SABSA model itself is generic and can be the starting point for any organization, but by going through the process of analysis and decision-making implied by its 
3722structure, it becomes specific to the enterprise, and is finally highly customized to a unique business model. It becomes in reality the enterprise security architecture, and it 
3723is central to the success of a strategic program of information security management within the organization. 
3724SABSA is a particular example of a methodology that can be used both for IT (Information Technology) and OT (Operational Technology) environments. 
3725
3726
3727
3728SOMF 
3729The service-oriented modeling framework (SOMF) has been proposed by author Michael Bell as a holistic and anthropomorphic modeling language for software 
3730development that employs disciplines and a universal language to provide tactical and strategic solutions to enterprise problems.[2] The term "holistic language" pertains 
3731to a modeling language that can be employed to design any application, business and technological environment, either local or distributed. This universality may include 
3732design of application-level and enterprise-level solutions, including SOA landscapes or cloud computing environments. The term "anthropomorphic", on the other hand, 
3733affiliates the SOMF language with intuitiveness of implementation and simplicity of usage. Furthermore, The SOMF language and its notation has been adopted by Sparx 
3734Enterprise Architect modeling platform that enables business architects, technical architects, managers, modelers, developers, and business and technical analysts to 
3735pursue the chief SOMF life cycle disciplines. 
3736SOMF is a service-oriented development life cycle methodology, a discipline-specific modeling process. It offers a number of modeling practices and disciplines that 
3737contribute to a successful service-oriented life cycle development and modeling during a project (see image on left). 
3738
3739Zachman framework 
3740The Zachman Framework is an Enterprise Architecture framework for enterprise architecture, which provides a formal and highly structured way of viewing and defining an 
3741enterprise. It consists of a two dimensional classification matrix based on the intersection of six communication questions (What, Where, When, Why, Who and How) with 
3742six levels of reification, successively transforming the abstract ideas on the Scope level into concrete instantiations of those ideas at the Operations level.[1] 
3743The Zachman Framework is a schema for organizing architectural artefacts (in other words, design documents, specifications, and models) that takes into account both 
3744whom the artefact targets (for example, business owner and builder) and what particular issue (for example, data and functionality) is being addressed.[2] The Zachman 
3745Framework is not a methodology in that it does not imply any specific method or process for collecting, managing, or using the information that it describes.[3] 
3746The Framework is named after its creator John Zachman, who first developed the concept in the 1980s at IBM. It has been updated several times since.[4] 
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756The term "Zachman Framework" has multiple meanings. It can refer to any of the frameworks proposed by John Zachman: 
3757The initial framework, named A Framework for Information Systems Architecture, by John Zachman published in an 1987 article in the IBM Systems journal.[5] 
3758The Zachman Framework for Enterprise Architecture, an update of the 1987 original in the 1990s extended and renamed .[6] 
3759One of the later versions of the Zachman Framework, offered by Zachman International as industry standard. 
3760Collage of Zachman Frameworks as presented in several books on Enterprise Architecture from 1997 to 2005. 
3761In other sources the Zachman Framework is introduced as a framework, originated by and named after John Zachman, represented in numerous ways, see image. This 
3762framework is explained as, for example: 
3763a framework to organize and analyze data,[7] 
3764a framework for enterprise architecture.[8] 
3765a classification system, or classification scheme[9] 
3766a matrix, often in a 6x6 matrix format 
3767a two-dimensional model[10] or an analytic model. 
3768a two-dimensional schema, used to organize the detailed representations of the enterprise.[11] 
3769Beside the frameworks developed by John Zachman numerous extensions and or applications have been developed, which are also sometimes called Zachman 
3770Frameworks. 
3771The Zachman Framework summarizes a collection of perspectives involved in enterprise architecture. These perspectives are represented in a two-dimensional matrix that 
3772defines along the rows the type of stakeholders and with the columns the aspects of the architecture. The framework does not define a methodology for an architecture. 
3773Rather, the matrix is a template that must be filled in by the goals/rules, processes, material, roles, locations, and events specifically required by the organization. Further 
3774modeling by mapping between columns in the framework identifies gaps in the documented state of the organization.[12] 
3775The framework is a simple and logical structure for classifying and organizing the descriptive representations of an enterprise. It is significant to both the management of 
3776the enterprise, and the actors involved in the development of enterprise systems.[13] While there is no order of priority for the columns of the Framework, the top-down 
3777order of the rows is significant to the alignment of business concepts and the actual physical enterprise. The level of detail in the Framework is a function of each cell (and 
3778not the rows). When done by IT the lower level of focus is on information technology, however it can apply equally to physical material (ball valves, piping, transformers, 
3779fuse boxes for example) and the associated physical processes, roles, locations etc. related to those items. 
3780
3781Orange Book 
3782The Trusted Computer System Evaluation Criteria (TCSEC) = ORANGE BOOK 
3783Focused on Confidentiality NOT integrity. 
3784One of the commonly cited deficiencies of the Orange Book is that it addresses only the operating system and does not include networks, databases, etc. 
3785According to the Orange book, Assurance refers to Operational Assurance, such as system architecture, protected execution domain, system integrity; and Life- 
3786Cycle Assurance, such as design methodology, security testing, and configuration. 
3787
3788Purpose: 
3789•   To provide a standard methodology for measuring the amount of trust you can place in a system  
3790•   To produce standards as to what security features for manufacturers to include when developing new commercial products.  
3791•   To provide government user personnel with a basis for the specific security requirements they were demanding when purchasing products. 
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803The Bell-LaPadula model is the security policy model on which the Orange Book requirements are based. From the Orange Book definition, "A formal state transition model 
3804of computer security policy that describes a set of access control rules. In this formal model, the entities in a computer system are divided into abstract sets of subjects and 
3805objects. The notion of secure state is defined and it is proven that each state transition preserves security by moving from secure state to secure state; thus, inductively 
3806proving the system is secure. A system state is defined to be 'secure' if the only permitted access modes of subjects to objects are in accordance with a specific security 
3807policy. In order to determine whether or not a specific access mode is allowed, the clearance of a subject is compared to the classification of the object and a determination 
3808is made as to whether the subject is authorized for the specific access mode." 
3809
3810The Orange book requires protection against two types of covert channels, Timing and Storage. 
3811Covert Storage Channel: A covert channel that involves writing to a storage location by one process and the direct or indirect reading of the storage location by another 
3812process. Covert storage channels typically involve a resource (for example, sectors on a disk) that is shared by two subjects at different security levels. 
3813Covert Timing Channel: A covert channel in which one process modulates its system resource (for example, CPU cycles), which is interpreted by a second process as some 
3814type of communication. 
3815
3816The TCSEC, frequently referred to as the Orange Book, is the centerpiece of the DoD Rainbow Series publications. 
3817Initially issued by the National Computer Security Center (NCSC) an arm of the National Security Agency in 1983 and then updated in 1985, TCSEC was replaced with the 
3818development of the Common Criteria international standard originally published in 2005. 
3819
3820
3821D – Minimal protection 
3822
3823
3824C – Discretionary protection 
3825C1 – Discretionary Security Protection 
3826•   C1 involves discretionary protection, C2 involves controlled access protection, B1 involves labeled security protection and B2 involves structured protection. 
3827
3828C2 – Controlled Access Protection 
3829•   Magnetic media must not have any remanence of previous data in order to be reused. This also applies to buffers, cache and other memory allocation and is required at 
3830    TCSEC C2 levels. 
3831
3832
3833B – Mandatory Protection 
3834B1 – Labeled Security 
3835•   Level B1 would be most similar to Compartmented Mode Workstations (CMW).   The CMW has many of the requirements of B1 with some of the requirements listed 
3836    under B2 and B3 as  well.  It fits the best with B1 as a level. 
3837•   B1 is also called "Labeled Security" and each data object must have a classification label and each subject a clearence label.  On each access attempt, the classification 
3838    and clearence are checked to verify that the access is permissible. 
3839•   Level B1 is the first to require design specification and verification and this would also be a requirement for all higher levels. 
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849B2 – Structured Protection 
3850•   the system must protect against covert storage channels.This class ("Structured Protection") requires more stringent authentication mechanisms and well-defined 
3851    interfaces between layers.  Subjects and devices require labels and the system must not allow covert channels. 
3852•   B2 security level requires that systems must support separate operator and system administrator roles. 
3853•   Level B2 is the first level to require configuration management and this would also be a requirement for all higher levels. 
3854•   Trusted facility management is an assurance requirement only for highly secure systems (B2, B3 and A1), but many systems evaluated a lower security levels are 
3855    structured to try to meet this requirement. 
3856•   Configuration management is the process of tracking and approving changes to a system. It is only required for B2, B3 and A1 level systems, but because it is common 
3857    sense, it is also recommended for systems that are evaluated at lower levels. 
3858
3859
3860B3 –  Security Domains 
3861•   Level B3 is the first level requiring Security Domains. 
3862•   At B3 and A1, systems must clearly identify the functions of the security administrator to perform the security-related functions. 
3863•   Trusted facility management is an assurance requirement only for highly secure systems (B2, B3 and A1), but many systems evaluated a lower security levels are 
3864    structured to try to meet this requirement. 
3865•   Configuration management is the process of tracking and approving changes to a system. It is only required for B2, B3 and A1 level systems, but because it is common 
3866    sense, it is also recommended for systems that are evaluated at lower levels. 
3867
3868
3869A – Verified Protection 
3870A1 – Verified Design 
3871•   Level A1 is Verified Design, this ensures nothing has been tampered with, not even the documentation so Trusted Distribution would be required at this level. 
3872•   At B3 and A1, systems must clearly identify the functions of the security administrator to perform the security-related functions. 
3873•   Trusted facility management is an assurance requirement only for highly secure systems (B2, B3 and A1), but many systems evaluated a lower security levels are 
3874    structured to try to meet this requirement. 
3875•   Configuration management is the process of tracking and approving changes to a system. It is only required for B2, B3 and A1 level systems, but because it is common 
3876    sense, it is also recommended for systems that are evaluated at lower levels. 
3877
3878
3879
3880
3881Common Criteria 
3882Assurance  
3883ITSEC + Orange Book + CTCPEC (Canadian) 
3884Common Criteria evaluations are performed on computer security products and systems. 
3885Protection profiles and security targets are elements of the ISO International Standard 15408 "Evaluation Criteria for Information Technology Security", also commonly known as the 
3886Common Criteria (CC).ISO 15408 is also know as Common Criteria.  Common Criteria terminology includes Protection Profiles and Security Target. This terminology was never used for ITSEC, 
3887only ToE was used so the correct answer would be ISO 15408. 
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897•   Target Of Evaluation (TOE) – the product or system that is the subject of the evaluation. 
3898The evaluation serves to validate claims made about the target. To be of practical use, the evaluation must verify the target's security features. This is done through the 
3899following: 
3900•   Protection Profile (PP) – a document, typically created by a user or user community, which identifies security requirements for a class of security devices (for 
3901    example, smart cards used to provide digital signatures, or network firewalls) relevant to that user for a particular purpose. Product vendors can choose to implement 
3902    products that comply with one or more PPs, and have their products evaluated against those PPs. In such a case, a PP may serve as a template for the product's ST 
3903    (Security Target, as defined below), or the authors of the ST will at least ensure that all requirements in relevant PPs also appear in the target's ST document. 
3904    Customers looking for particular types of products can focus on those certified against the PP that meets their requirements. 
3905•   Security Target (ST) – the document that identifies the security properties of the target of evaluation. It may refer to one or more PPs. The TOE is evaluated against the 
3906    SFRs (see below) established in its ST, no more and no less. This allows vendors to tailor the evaluation to accurately match the intended capabilities of their product. 
3907    This means that a network firewall does not have to meet the same functional requirements as a database management system, and that different firewalls may in fact 
3908    be evaluated against completely different lists of requirements. The ST is usually published so that potential customers may determine the specific security features 
3909    that have been certified by the evaluation. 
3910•   Security Functional Requirements (SFRs) – specify individual security functions which may be provided by a product. The Common Criteria presents a standard 
3911    catalogue of such functions. For example, a SFR may state how a user acting a particular role might be authenticated. The list of SFRs can vary from one evaluation to 
3912    the next, even if two targets are the same type of product. Although Common Criteria does not prescribe any SFRs to be included in an ST, it identifies dependencies 
3913    where the correct operation of one function (such as the ability to limit access according to roles) is dependent on another (such as the ability to identify individual 
3914    roles). 
3915The evaluation process also tries to establish the level of confidence that may be placed in the product's security features through quality assurance processes: 
3916•   Security Assurance Requirements (SARs) – descriptions of the measures taken during development and evaluation of the product to assure compliance with the 
3917    claimed security functionality. For example, an evaluation may require that all source code is kept in a change management system, or that full functional testing is 
3918    performed. The Common Criteria provides a catalogue of these, and the requirements may vary from one evaluation to the next. The requirements for particular 
3919    targets or types of products are documented in the ST and PP, respectively. 
3920•   Evaluation Assurance Level (EAL) – the numerical rating describing the depth and rigor of an evaluation. Each EAL corresponds to a package of security assurance 
3921    requirements (SARs, see above) which covers the complete development of a product, with a given level of strictness. Common Criteria lists seven levels, with EAL 1 
3922    being the most basic (and therefore cheapest to implement and evaluate) and EAL 7 being the most stringent (and most expensive). Normally, an ST or PP author will 
3923    not select assurance requirements individually but choose one of these packages, possibly 'augmenting' requirements in a few areas with requirements from a higher 
3924    level. Higher EALs do not necessarily imply "better security", they only mean that the claimed security assurance of the TOE has been more extensively verified. 
3925So far, most PPs and most evaluated STs/certified products have been for IT components (e.g., firewalls, operating systems, smart cards). Common Criteria certification is 
3926sometimes specified for IT procurement. Other standards containing, e.g., interoperation, system management, user training, supplement CC and other product standards. 
3927Examples include the ISO/IEC 17799 (Or more properly BS 7799-1, which is now ISO/IEC 27002) or the German IT-Grundschutzhandbuch. 
3928Details of cryptographic implementation within the TOE are outside the scope of the CC. Instead, national standards, like FIPS 140-2 give the specifications for cryptographic 
3929modules, and various standards specify the cryptographic algorithms in use. 
3930More recently, PP authors are including cryptographic requirements for CC evaluations that would typically be covered by FIPS 140-2 evaluations, broadening the bounds of 
3931the CC through scheme-specific interpretations. 
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941According to the Common Criteria, an intermediate combination of security requirement components is termed a package. The package permits the expression of a 
3942set of either functional or assurance requirements that meet some particular need, expressed as a set of security objectives. A package may be used in the construction of 
3943more complex packages or Protection Profiles and Security Targets. The seven evaluation assurance levels (EALs) are predefined assurance packages. The TOE is an IT 
3944product or system to be evaluated. 
3945
3946
3947Under the Common Criteria model, an evaluation is carried out on a product and is assigned an Evaluation Assurance Level (EAL). The thorough and stringent testing 
3948increases in detailed-oriented tasks as the assurance levels increase. The Common Criteria has seven assurance levels. The range is from EAL1, where functionality testing 
3949takes place, to EAL7, where thorough testing is performed and the system design is verified.  
3950The Orange Book and the Rainbow Series provide evaluation schemes that are too rigid and narrowly defined for the business world. ITSEC attempted to provide a more 
3951flexible approach by separating the functionality and assurance attributes and considering the evaluation of entire systems. However, this flexibility added complexity 
3952because evaluators could mix and match functionality and assurance ratings, which resulted in too many classifications to keep straight.  
3953Because we are a species that continues to try to get it right, the next attempt for an effective and usable evaluation criteria was the Common Criteria. In 1990, the 
3954International Organization for Standardization (ISO) identified the need for international standard evaluation criteria to be used globally. The Common Criteria project 
3955started in 1993 when several organizations came together to combine and align existing and emerging evaluation criteria (TCSEC, ITSEC, Canadian Trusted Computer 
3956Product Evaluation Criteria [CTCPEC], and the Federal Criteria).  
3957The Common Criteria was developed through a collaboration among national security standards organizations within the United States, Canada, France, Germany, the 
3958United Kingdom, and the Netherlands. The benefit of having a globally recognized and accepted set of criteria is that it helps consumers by reducing the complexity of the 
3959ratings and eliminating the need to understand the definition and meaning of different ratings within various evaluation schemes. This also helps vendors, because now 
3960they can build to one specific set of requirements if they want to sell their products internationally, instead of having to meet several different ratings with varying rules and 
3961requirements. 
3962The full list of assurance requirements for the Evaluation Assurance Levels is provided below: 
3963•   EAL 1: The product is functionally tested; this is sought when some assurance in accurate operation is necessary, but the threats to security are not seen as serious.  
3964•   EAL 2: Structurally tested; this is sought when developers or users need a low to moderate level of independently guaranteed security.  
3965•   EAL 3: Methodically tested and checked; this is sought when there is a need for a moderate level of independently ensured security.  
3966•   EAL 4: Methodically designed, tested, and reviewed; this is sought when developers or users require a moderate to high level of independently ensured security.  
3967•   EAL 5: Semiformally designed and tested; this is sought when the requirement is for a high level of independently ensured security.  
3968•   EAL 6: Semiformally verified, designed, and tested; this is sought when developing specialized TOEs for high-risk situations.  
3969•   EAL 7: Formally verified, designed, and tested; this is sought when developing a security TOE for application in extremely high-risk situations.  
3970EALs are frequently misunderstood to provide a simple means to compare security products with similar levels. In fact, products may be very different even if they are 
3971assigned the same EAL level, since functionality may have little in common. 
3972
3973
3974SEI-CMM – Security Engineering Institute – Capability Maturity Model 
3975Software Framework 
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987The Capability Maturity Model (CMM) is a service mark owned by Carnegie Mellon University (CMU) and refers to a development model elicited from actual data. The data 
3988was collected from organizations that contracted with the U.S. Department of Defense, who funded the research, and became the foundation from which CMU created the 
3989Software Engineering Institute (SEI). Like any model, it is an abstraction of an existing system.  
3990
3991The Capability Maturity Model (CMM) is a methodology used to develop and refine an organization's software development process. The model describes a five-level 
3992evolutionary path of increasingly organized and systematically more mature processes. CMM was developed and is promoted by the Software Engineering Institute (SEI), a 
3993research and development center sponsored by the U.S. Department of Defense (DoD). SEI was founded in 1984 to address software engineering issues and, in a broad 
3994sense, to advance software engineering methodologies. More specifically, SEI was established to optimize the process of developing, acquiring, and maintaining heavily 
3995software-reliant systems for the DoD. Because the processes involved are equally applicable to the software industry as a whole, SEI advocates industry-wide adoption of 
3996the CMM. 
3997The CMM is similar to ISO 9001, one of the ISO 9000 series of standards specified by the International Organization for Standardization (ISO). The ISO 9000 standards 
3998specify an effective quality system for manufacturing and service industries; ISO 9001 deals specifically with software development and maintenance. The main difference 
3999between the two systems lies in their respective purposes: ISO 9001 specifies a minimal acceptable quality level for software processes, while the CMM establishes a 
4000framework for continuous process improvement and is more explicit than the ISO standard in defining the means to be employed to that end.  
4001CMM's Five Maturity Levels of Software Processes: 
4002At the initial level, processes are disorganized, even chaotic. Success is likely to depend on individual efforts, and is not considered to be repeatable, because processes 
4003would not be sufficiently defined and documented to allow them to be replicated.  
4004At the repeatable level, basic project management techniques are established, and successes could be repeated, because the requisite processes would have been made 
4005established, defined, and documented.  
4006At the defined level, an organization has developed its own standard software process through greater attention to documentation, standardization, and integration.  
4007At the managed level, an organization monitors and controls its own processes through data collection and analysis.  
4008At the optimizing level, processes are constantly being improved through monitoring feedback from current processes and introducing innovative processes to better serve 
4009the organization's particular needs. 
4010
4011
4012
4013
40144.A.3 Supervisory Control and Data Acquisition (SCADA) (e.g., process automation networks, work interdependencies, monitoring requirements) 
4015
4016
40174.B Perform requirements analysis 
40184.B.1 Business and functional requirements(e.g. locations, jurisdictions, business sectors, cost, stakeholder preferences, quality attributes, capacity, manageability) 
40194.B.2 Treat modeling 
40204.B.3 Evaluate use cases (e.g. business rules and control objectives, misuse, abuse) 
40214.B.4 Gap analysis 
40224.B.5 Assess risk 
40234.B.6 Maturity models 
4024
4025
40264.C Design security architecture 
40274.C.1 Apply existing information security standards and guidelines (e.g. ISO/IEC, PCI, NIST) 
40284.C.2 Systems development Life Cycle (SDLC) (e.g. requirements traceability matrix, security architecture documentation, secure coding) 
4029
4030
4031
4032
4033
4034
4035
40364.C.3 Application Security (e.g., Commercial Off-the-Shelf (COTS) integration) 
4037
4038
40394.D Verify and validate design 
40404.D.1 Validate threat model (e.g. access control attacks, cryptanalytic attacks, network attacks) 
40414.D.2 Evaluate controls against threats and vulnerabilities 
40424.D.3 Remediate gaps 
40434.D.4 Independent verification and validation 
4044
4045Accreditation is the authorization by management to implement software or systems in a production environment.  This authorization may be either provisional or full. 
4046Accreditation is the official management decision to operate a system.  Accreditation is the formal declaration by a senior agency official (Designated Accrediting Authority 
4047(DAA) or Principal Accrediting Authority (PAA)) that an information system is approved to operate at an acceptable level of risk, based on the implementation of an 
4048approved set of technical, managerial, and procedural security controls (safeguards). 
4049
4050Certification is the process of evaluating the security stance of the software or system against a selected set of standards or policies.  Certification is the technical 
4051evaluation of a product.  This may precede accreditation but is not a required precursor. Certification is the process of performing a comprehensive analysis of the security 
4052features and safeguards of a system to establish the extent to which the security requirements are satisfied.  Shon Harris states in her book that Certification is the 
4053comprehensive technical evaluation of the security components and their compliance for the purpose of accreditation. 
4054
4055Evaluation as a general term is described as the process of independently assessing a system against a standard of comparison, such as evaluation criteria.  Evaluation 
4056criterias are defined as a benchmark, standard, or yardstick against which accomplishment, conformance, performance, and suitability of an individual, hardware, software, 
4057product, or plan, as well as of risk-reward ratio is measured. 
4058
4059Acceptance testing refers to user testing of a system before accepting delivery. 
4060
4061-------------------- 
4062OTHERS 
4063
4064
4065AIO defines Compartmented Mode Workstation (CMW) as a workstation that contains the necessary controls to be able to operate as a trusted computer. The system is 
4066trusted to keep data from different classification levels and categories in separate compartments and properly protected. 
4067Information Labels are similar to Sensitivity Labels, but in addition to the classification and the category set of the Sensitivity Labels, they also have the necessary controls 
4068to be able to operate as a trusted computer. 
4069
4070The AIO defines Object Reuse as reassigning to a subject media that previously contained information. Object reuse is a security concern because if insufficient measures 
4071were taken to erase the information on the media, the information may be disclosed to unauthorized personnel.  This is a big issue when you think of shared resources such 
4072as RAM where a portion might be assigned to an application ten reassigned to another application a bit later.   The memory manager must do a full refresh of the memory 
4073area before it is reassigned to another application.  
4074Allowing objects to be used sequentially by multiple users without a refresh of the objects can lead to disclosure of residual data. It is important that steps be taken to 
4075eliminate the chance for the disclosure of residual data. 
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085Ring Architecture  
4086In computer science, hierarchical protection domains, often called protection rings, are a mechanism to protect data and functionality from faults (fault tolerance) and 
4087malicious behavior (computer security). This approach is diametrically opposite to that of capability-based security. 
4088Computer operating systems provide different levels of access to resources. A protection ring is one of two or more hierarchical levels or layers of privilege within the 
4089architecture of a computer system. This is generally hardware-enforced by some CPU architectures that provide different CPU modes at the hardware or microcode level. 
4090Rings are arranged in a hierarchy from most privileged (most trusted, usually numbered zero) to least privileged (least trusted, usually with the highest ring number). On 
4091most operating systems, Ring 0 is the level with the most privileges and interacts most directly with the physical hardware such as the CPU and memory. 
4092Special gates between rings are provided to allow an outer ring to access an inner ring's resources in a predefined manner, as opposed to allowing arbitrary usage. Correctly 
4093gating access between rings can improve security by preventing programs from one ring or privilege level from misusing resources intended for programs in another. For 
4094example, spyware running as a user program in Ring 3 should be prevented from turning on a web camera without informing the user, since hardware access should be a 
4095Ring 1 function reserved for device drivers. Programs such as web browsers running in higher numbered rings must request access to the network, a resource restricted to a 
4096lower numbered ring. 
4097
4098Trusted Computing Base (TCB) is responsible for providing security. Limited Privilege is assured by isolating the resources that are protected . Processes running in one 
4099domain often invoke processes in other domains to obtain more sensitive data or services. The TCB ensures that the processes provide security by granting minimal 
4100privilege, not more than needed. 
4101The Trusted Computing Base (TCB) is the totality of protection mechanisms within a computer system — including hardware, firmware, software, processes, and some 
4102inter-process communications — that, combined, are responsible for enforcing a security policy. 
4103TCB is: 
4104•   It is defined in the Orange Book.  
4105•   It includes hardware, firmware and software.  
4106•   A higher TCB rating will require that details of their testing procedures and documentation be reviewed with more granularity. 
4107
4108
4109
4110DIACAP  
4111DITSCAP has been replaced by DIACAP (DoD Information Assurance Certification and Accreditation Process) effective Nov 2007 for C&A within the Department of Defense.   
4112The DoD Information Assurance Certification and Accreditation Process (DIACAP) is the United States Department of Defense (DoD) process to ensure that risk management 
4113is applied on information systems (IS). DIACAP defines a DoD-wide formal and standard set of activities, general tasks and a management structure process for the 
4114certification and accreditation (C&A) of a DoD IS that will maintain the information assurance (IA) posture throughout the system's life cycle. 
4115An interim version of the DIACAP was signed July 6, 2006 and superseded DITSCAP. The final version is titled Department of Defense Instruction 8510.01 and was signed on 
4116November 28, 2007. It supersedes the Interim DIACAP Guidance. 
4117NIACAP 
4118National Information Assurance Certification and Accreditation Process (NIACAP), establishes the minimum national standards for certifying and accrediting national 
4119security systems. This process provides a standard set of activities, general tasks, and a management structure to certify and accredit systems that will maintain the 
4120Information Assurance (IA) and security posture of a system or site. 
4121HIPAA 
4122The HIPAA legislation had four primary objectives:  
4123
4124
4125
4126
4127
4128
4129
4130(1) Assure health insurance portability by eliminating job-lock due to pre-existing medical conditions,  
4131(2) Reduce healthcare fraud and abuse,  
4132(3) Enforce standards for health information and  
4133(4) Guarantee security and privacy of health information. 
4134NIST 
4135The correct answer is ' The National Institute of Standards and Technology (NIST) ' as FIPS publications are issued by NIST after approval by the Secretary of Commerce 
4136pursuant to Section 5131 of the Information Technology Reform Act of 1996, Public Law 104-106, and the FISMA Act of 2002. 
4137
4138
4139
4140As per FDA data should be attributable, original, accurate, contemporaneous and legible. In an automated system attributability could be achieved by a computer 
4141system designed to identify individuals responsible for any input. 
4142
4143
4144
4145The reference monitor refers to abstract machine that mediates all access to objects by subjects. 
4146This question is asking for the concept that governs access by subjects to objects, thus the reference monitor is the best answer.  While the security kernel is similar in 
4147nature, it is what actually enforces the concepts outlined in the reference monitor.  
4148
4149In operating systems architecture a reference monitor concept defines a set of design requirements on a reference validation mechanism, which enforces an access control 
4150policy over subjects' (e.g., processes and users) ability to perform operations (e.g., read and write) on objects (e.g., files and sockets) on a system. The properties of a 
4151reference monitor are: 
4152The reference validation mechanism must always be invoked (complete mediation). Without this property, it is possible for an attacker to bypass the mechanism and 
4153violate the security policy.The reference validation mechanism must be tamperproof (tamperproof). Without this property, an attacker can undermine the mechanism itself 
4154so that the security policy is not correctly enforced.The reference validation mechanism must be small enough to be subject to analysis and tests, the completeness of 
4155which can be assured (verifiable). Without this property, the mechanism might be flawed in such a way that the policy is not enforced. 
4156Reference Monitor is used to compare the security labels of a subject and an object. 
4157The reference monitor must meet three conditions:  
4158(1) it must be tamperproof (isolation) 
4159(2) it must be invoked on every access to every object (completeness) and  
4160(3) it must be small enough for thorough validation of its operation through analysis and tests, in order to verify completeness (verifiability). 
4161
4162
4163
4164Process isolation is where each process has its own distinct address space for its application code and data. In this way, it is possible to prevent each process from 
4165accessing another process' data. This prevents data leakage, or modification to the data while it is in memory. Memory segmentation is a virtual memory management 
4166mechanism. The reference monitor is an abstract machine that mediates all accesses to objects by subjects. Data hiding, also known as information hiding, is a mechanism 
4167that makes information available at one processing level is not available at another level. 
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177In dedicated security mode, all users have a clearence and formal need to know for all information processed within the system.  If for example, the system stores 
4178and processes top secret information on the "Nova Widgets" program, then all users of the system must have both a top secret clearence and a formal need to know for 
4179the "Nova Widgets" program. 
4180
4181Trusted System does: 
4182•   Enforcement of a security policy.  
4183•   Sufficiency and effectiveness of mechanisms to be able to enforce a security policy. 
4184•   Independently-verifiable evidence that the security policy-enforcing mechanisms are sufficient and effective. 
4185
4186Goals of Integrity: 
4187•   Prevent unauthorized users from making modifications.  
4188•   Maintain internal and external consistency.  
4189•   Prevent authorized users from making improper modifications. 
4190
4191
4192
4193CISC: 
4194Complex Instruction Set Computer (CISC) uses instructions that perform many operations per instruction. It was based on the fact that in earlier technologies, the 
4195instruction fetch was the longest part of the cycle. Therefore, by packing more operations into an instruction, the number of fetches could be reduced. Pipelining involves 
4196overlapping the steps of different instructions to increase the performance in a computer. Reduced Instruction Set Computers (RISC) involve simpler instructions that 
4197require fewer clock cycles to execute. Scalar processors are processors that execute one instruction at a time. 
4198
4199Pipelining is a natural concept in everyday life, e.g. on an assembly line. Consider the assembly of a car: assume that certain steps in the assembly line are to install the 
4200engine, install the hood, and install the wheels (in that order, with arbitrary interstitial steps). A car on the assembly line can have only one of the three steps done at once.  
4201After the car has its engine installed, it moves on to having its hood installed, leaving the engine installation facilities available for the next car. The first car then moves on 
4202to wheel installation, the second car to hood installation, and a third car begins to have its engine installed. If engine installation takes 20 minutes, hood installation takes 5 
4203minutes, and wheel installation takes 10 minutes, then finishing all three cars when only one car can be assembled at once would take 105 minutes. On the other hand, 
4204using the assembly line, the total time to complete all three is 75 minutes. At this point, additional cars will come off the assembly line at 20 minute increments.  
4205
4206In computing, a pipeline is a set of data processing elements connected in series, so that the output of one element is the input of the next one. The elements of a pipeline 
4207are often executed in parallel or in time-sliced fashion; in that case, some amount of buffer storage is often inserted between elements.  Pipelining is used in processors to 
4208allow overlapping execution of multiple instructions within the same circuitry. The circuitry is usually divided into stages, including instruction decoding, arithmetic, and 
4209register fetching stages, wherein each stage processes one instruction at a time. 
4210Very-Long Instruction-Word Processor (VLIW) - a computer processing architecture in which a language compiler or pre-processor breaks program 
4211instructions down into basic operations that can be performed by the processor at the same time. 
4212
4213A fault-tolerant system is capable of detecting that a fault has occurred and has the ability to correct the fault or operate around it. In a fail-safe system, program execution 
4214is terminated, and the system is protected from being compromised when a hardware or software failure occurs and is detected. In a fail-soft system, when a hardware or 
4215
4216
4217
4218
4219
4220
4221
4222software failure occurs and is detected, selected, non-critical processing is terminated. The term failover refers to switching to a duplicate "hot" backup component in real- 
4223time when a hardware or software failure occurs, enabling processing to continue. 
4224
4225Fail over - When one system/application fails, operations will automatically switch to the backup system.  
4226Fail safe - Pertaining to the automatic protection of programs and/or processing systems to maintain safety when a hardware or software failure is detected in a system.  
4227Fail secure - The system preserves a secure state during and after identified failures occur.  
4228Fail soft - Pertaining to the selective termination of affected non-essential processing when a hardware or software failure is detected in a system 
4229
4230The Graham–Denning is primarily concerned with how subjects and objects are created, how subjects are assigned rights or privileges, and how ownership of objects is 
4231managed. In other words, it is primarily concerned with how a model system controls subjects and objects at a very basic level where other models simply assumed such 
4232control. 
4233The Graham–Denning access control model has three parts: a set of objects, a set of subjects, and a set of rights. 
4234"The Graham—Denning access control model defines eight primitive protection rights:  
42351. Create object: the ability to create a new object 
42362. Create subject: the ability to create a new subject  
42373. Delete object: the ability to delete an existing object  
42384. Delete subject: the ability to delete an existing subject 
42395. Read access right: the ability to view current access privileges 
42406. Grant access right: the ability to grant access privileges 
42417. Delete access right: the ability to remove access privileges 
42428. Transfer access right: the ability to transfer access privileges from one subject or object to another subject or object" 
4243
4244"system high" security policy - system where all users are cleared to view the most highly classified data on the system. 
4245
4246Configuration Management as: The use of procedures appropriate for controlling changes to a system’s hardware, software, or firmware structure to ensure that 
4247such changes will not lead to a weakness or fault in the system. 
4248
4249TCSEC focused on confidentiality while ITSEC added integrity and availability as security goals. 
4250Information Technology Security Evaluation Criteria (ITSEC).Following the release of the Orange Book, several European countries issued their own criteria. The 
4251European Information Technology Security Evaluation Criteria (ITSEC) was first drafted in 1990 and became endorsed by the Council of the European Union in 1995. It was 
4252the result of Dutch, English, French, and German activities designed to define and harmonize European national security evaluation criteria. Although ITSEC includes 
4253concepts from the TCSEC, the Orange Book was thought to be too rigid. Thus, ITSEC attempted to provide a framework for security evaluation that would be more flexible. 
4254One major difference between the two is ITSEC’s inclusion of integrity and availability as security goals, along with confidentiality. 
4255
4256Data mining is used to reveal hidden relationships, patterns and trends by running queries on large data stores. 
4257
4258
4259
4260How to protect objects and the data within the object? 
4261
4262
4263
4264
4265
4266
4267Layering assigns specific functions to each layer and communication between layers is only possible through well-defined interfaces.  This helps preclude tampering in 
4268violation of security policy. 
4269Abstraction "hides" the particulars of how an object functions or stores information and requires the object to be manipulated through well-defined interfaces that can be 
4270designed to enforce security policy. 
4271Data hiding conceals the details of information storage and manipulation within an object by only exposing well defined interfaces tot he information rather than the 
4272information itslef.  For example, the details of how passwords are stored could be hidden inside a password object with exposed interfaces such as check_password, 
4273set_password, etc.  When a password needs to be verified, the test password is passed to the check_password method and a boolean (true/false) result is returned to 
4274indicate if the password is correct without revealing any details of how/where the real passwords are stored. 
4275
4276The noninterference model is the correct answer. The goal of a noninterference model is to strictly separate differing security levels to assure that higher-level actions do 
4277not determine what lower-level users can see.  This is in contrast to other security models that control information flows between differing levels of users,  By maintaining 
4278strict separation of security levels, a noninterference model minimizes leakages that might happen through a covert channel. 
4279
4280An over channel is a path within a computer system or network that is designed for the authorized transfer of data.  The opposite would be a covert channel which is an 
4281unauthorized path. 
4282A covert channel is a way for an entity to receive information in an unauthorized manner. It is an information flow that is not controlled by a security mechanism. This 
4283type of information path was not developed for communication; thus, the system does not properly protect this path, because the developers never envisioned information 
4284being passed in this way. Receiving information in this manner clearly violates the system’s security policy. 
4285
4286A security domain is a domain of trust that shares a single security policy and single management.  
4287The term security domain just builds upon the definition of domain by adding the fact that resources within this logical structure (domain) are working under the same 
4288security policy and managed by the same group.  
4289So, a network administrator may put all of the accounting personnel, computers, and network resources in Domain 1 and all of the management personnel, computers, and 
4290network resources in Domain 2. These items fall into these individual containers because they not only carry out similar types of business functions, but also, and more 
4291importantly, have the same type of trust level. It is this common trust level that allows entities to be managed by one single security policy.  
4292The different domains are separated by logical boundaries, such as firewalls with ACLs, directory services making access decisions, and objects that have their own ACLs 
4293indicating which individuals and groups can carry out operations on them.  
4294All of these security mechanisms are examples of components that enforce the security policy for each domain. Domains can be architected in a hierarchical manner that 
4295dictates the relationship between the different domains and the ways in which subjects within the different domains can communicate. Subjects can access resources in 
4296domains of equal or lower trust levels. 
4297
4298Security Kernel 
4299•   The security kernel is made up of mechanisms that fall under the TCB and implements and enforces the reference monitor concept.  
4300•   The security kernel must provide isolation for the processes carrying out the reference monitor concept and they must be tamperproof.  
4301•   The security kernel must be small enough to be able to be tested and verified in a complete and comprehensive manner. 
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312Indirect addressing is when the address location that is specified in the program instruction contains the address of the final desired location. Direct addressing is 
4313when a portion of primary memory is accessed by specifying the actual address of the memory location. Indexed addressing is when the contents of the address defined in 
4314the program's instruction is added to that of an index register. Program addressing is not a defined memory addressing mode. 
4315
4316The security perimeter is the imaginary line that separates the trusted components of the kernel and the Trusted Computing Base (TCB) from those elements that are not 
4317trusted. The reference monitor is an abstract machine that mediates all accesses to objects by subjects. The security kernel can be software, firmware or hardware 
4318components in a trusted system and is the actual instantiation of the reference monitor. The reference perimeter is not defined and is a distracter. 
4319
4320
4321Simple Security Property and Polyinstantiation 
4322The Simple Security Property states that a subject at a given clearance may not read an object at a higher classification, so unclassified APFEL could not read FIGCO's top 
4323secret cargo information.  
4324Polyinstantiation permits a database to have two records that are identical except for their classifications (i.e., the primary key includes the classification). Thus, APFEL's 
4325new unclassified record did not collide with the real, top secret record, so APFEL was not able to learn about FIGs pineapples. 
4326
4327The Brewer and Nash model was constructed to provide information security access controls that can change dynamically.  This security model, also known as the Chinese 
4328wall model, was designed to provide controls that mitigate conflict of interest in commercial organizations, and is built upon an information flow model. 
4329In the Brewer and Nash Model no information can flow between the subjects and objects in a way that would create a conflict of interest. 
4330
4331Middleware is a connectivity software that enables multiple processes running on one or more machines to interact. 
4332
4333Pervasive Computing and Mobile Computing Devices 
4334•   These devices share common security concerns with other resource-constrained devices.  
4335•   In many cases, security services have been sacrificed to provide richer user interaction when processing power is very limited.  
4336•   Their mobility has made them a prime vector for data loss since they can be used to transmit and store information in ways that may be difficult to control. 
4337
4338
4339
4340Compartmented security mode allows a system to have differing levels of information and all users have clearence to access all the information (which means 
4341they must be cleared to access the highest level of information stored and processed on the sytem) but not all users have the need to know. 
4342Multilevel security mode. In multi-level mode, the system stores and processes information of differing classifications but users are only required to have clearence 
4343and need to know for the information they need to access. For example, multilevel security would allow a system that processes confidential and secret information to be 
4344accessed by users with clearences of confidential and secret but the system would impose controls to assure that each user only accesses information for which they have 
4345both clearence and formal need to know.  
4346System-high security mode. System-high security mode requires all users to have a clearence for the level of information stored and processed by the system but 
4347all users have a need to know for only some of the data stored and processed by the system. For example, though all information on "Nova Widgets" is top secret and all 
4348users of the system must therefore have a top secret clearence, some users may only have a need to know for "Nova Widgets Ordnance" information while other users may 
4349only have a need to know for the "Nova Widgets Guidance and Propulsion" information.  
4350
4351
4352
4353
4354
4355
4356
4357
4358Dedicated security mode. In dedicated security mode, all users have a clearence and formal need to know for all information processed within the system. If for 
4359example, the system stores and processes top secret information on the "Nova Widgets" program, then all users of the system must have both a top secret clearence and a 
4360formal need to know for the "Nova Widgets" program. 
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
44105 Technology related business continuity planning (BCP) & Disaster recovery planning (DRP) 
4411
44125.A Incorporate business impact analysis (BIA) requirements (e.g. legal, financial, stakeholders) 
4413The Business Impact Analysis (BIA) identifies time-critical aspects of the critical business processes, and determines their maximum tolerable downtime.  The BIA helps to 
4414Identify organization functions, the capabilities of each organization unit to handle outages, and the priority and sequence of functions and applications to be recovered, 
4415identify resources required for recovery of those areas and interdependencies 
4416In performing the Business Impact Analysis (BIA) it is very important to consider what the dependencies are. You cannot bring a system up if it depends on another system 
4417to be operational. You need to look at not only internal dependencies but external as well. You might not be able to get the raw materials for your business so 
4418dependencies are very important aspect of a BIA. 
4419The BIA committee will not truly understand all business processes, the steps that must take place, or the resources and supplies these processes require. So the committee 
4420must gather this information from the people who do know— department managers and specific employees throughout the organization. The committee starts by 
4421identifying the people who will be part of the BIA data-gathering sessions. The committee needs to identify how it will collect the data from the selected employees, be it 
4422through surveys, interviews, or workshops. Next, the team needs to collect the information by actually conducting surveys, interviews, and workshops. Data points 
4423obtained as part of the information gathering will be used later during analysis. It is important that the team members ask about how different tasks— whether processes, 
4424transactions, or services, along with any relevant dependencies— get accomplished within the organization. 
4425BIA - provides enterprise management with: 
4426•   a prioritized list of time-critical  business processes.  
4427•   estimates a recovery time objective for each of the time critical processes. 
4428•   the components of the enterprise that support those processes. 
4429There have been much discussion about the steps of the BIA and I struggled with this before deciding to scrape the question about "the four steps," and re-write the 
4430question using the AIO for a reference.   This question should be easy.... if you know all eight steps. 
4431The eight detailed and granular steps of the BIA are: 
44321.  Select Individuals to interview for the data gathering. 
44332.  Create data gathering techniques (surveys, questionnaires, qualitative and quantitative approaches). 
44343.  Identify the company's critical business functions. 
44354.  Identify the resources that these functions depend upon. 
44365.  Calculate how long these functions can survive without these resources. 
44376.  Identify vulnerabilities and the threats to these functions. 
44387.  Calculate risk for each of the different business functions. 
44398.  Document findings and report them to management.  
4440
4441
4442Goals of BIA 
4443Criticality prioritization, downtime estimation, and resource requirments are the three primary goals of a BIA. Data processing continuity planning, data recovery plan 
4444maintenance, and testing the disaster recovery plan are steps in the DRP process. Scope and plan initiation, business continuity plan development, and plan approval and 
4445
4446
4447
4448
4449
4450
4451
4452implementation are the other 3 elements of BCP. Facility requirements planning, facility security management, and administrative personnel controls are elements of 
4453administrative controls in Physical Security. 
4454
4455
4456Vulnerability analysis outcomes: 
4457Quantitative loss criteria may be defined as follows: 
4458- Incurring financial losses from loss of revenue, capital expenditure, or personal liability resolution 
4459- The additional operational expenses incurred due to the disruptive event 
4460- Incurring financial loss from resolution of violation of contract agreements 
4461- Incurring financial loss from resolution of violation of regulatory or compliance requirements 
4462
4463
4464Qualitative loss criteria may consist of the following: 
4465- The loss of competitive advantage or market share 
4466- The loss of public confidence or credibility, or incurring public mbarrassment 
4467During  the vulnerability assessment,  critical support areas must be defined in order to assess the impact of a disruptive event. A critical support area is defined as a 
4468business  unit or function that must be present to sustain continuity of the business processes, maintain life safety, or avoid public relations embarrassment. 
4469
4470
4471Critical support areas could include the following: 
4472- Telecommunications, data communications, or information technology areas 
4473- Physical infrastructure or plant facilities, transportation services 
4474- Accounting, payroll, transaction processing, customer service, purchasing  
4475The granular elements of these critical support areas will also need to be identified. By granular elements we mean the personnel, resources, and services the critical 
4476support areas need to maintain business continuity 
4477
4478
4479IT contingency planning represents a broad scope of activities designed to sustain and recover critical IT services following an emergency. IT contingency planning fits into a 
4480much broader emergency preparedness environment that includes organizational and business process continuity and recovery planning. Ultimately, an organization would 
4481use a suite of plans to properly prepare response, recovery, and continuity activities for disruptions affecting the organization’s IT systems, business processes, and the 
4482facility. Because there is an inherent relationship between an IT system and the business process it supports, there should be coordination between each plan during 
4483development and updates to ensure that recovery strategies and supporting resources neither negate each other nor duplicate efforts.  
4484Disaster Recovery Plan (DRP) 
4485As suggested by its name, the DRP applies to major, usually catastrophic, events that deny access to the normal facility for an extended period.  Frequently, DRP refers to an 
4486IT-focused plan designed to restore operability of the target system, application, or computer facility at an alternate site after an emergency. The DRP scope may overlap 
4487that of an IT contingency plan (see below); however, the DRP is narrower in scope and does not address minor disruptions that do not require relocation.  Dependent on 
4488the organization’s needs, several DRPs may be appended to the BCP.  
4489
4490
4491
4492
4493
4494
4495
4496Business Continuity Plan (BCP) 
4497The BCP focuses on sustaining an organization’s business functions during and after a disruption. An example of a business function may be an organization’s payroll 
4498process or consumer information process. A BCP may be written for a specific business process or may address all key business processes. IT systems are considered in the 
4499BCP in terms of their support to the business processes. In some cases, the BCP may not address long-term recovery of processes and return to normal operations, solely 
4500covering interim business continuity requirements. A disaster recovery plan, business resumption plan, and occupant emergency plan may be appended to the BCP. 
4501Responsibilities and priorities set in the BCP should be coordinated with those in the Continuity of Operations Plan (COOP) to eliminate possible conflicts. 
4502STEPS: 
45031.Develop the contingency planning policy statement and initiation of the project. 
4504A formal policy provides the authority and guidance necessary to develop an effective contingency plan. 
45052. Conduct the business impact analysis (BIA). 
4506The BIA helps identify and prioritize information systems and components critical to supporting the organization’s mission/business functions. A template for developing 
4507the BIA is provided to assist the user. 
45083. Identify preventive controls. 
4509Measures taken to reduce the effects of system disruptions can increase system availability and reduce contingency life cycle costs. 
45104. Create contingency strategies. 
4511Thorough recovery strategies ensure that the system may be recovered quickly and effectively following a disruption. 
45125. Develop an information system contingency plan. 
4513The contingency plan should contain detailed guidance and procedures for restoring a damaged system unique to the system’s security impact level and recovery 
4514requirements. 
45156. Ensure plan testing, training, and exercises. 
4516Testing validates recovery capabilities, whereas training prepares recovery personnel for plan activation and exercising the plan identifies planning gaps; combined, the 
4517activities improve plan effectiveness and overall organization preparedness. 
45187. Ensure plan maintenance. 
4519The plan should be a living document that is updated regularly to remain current with system enhancements and organizational changes. 
4520
4521
4522Business Recovery Plan (BRP), also called the Business Resumption Plan 
4523The BRP addresses the restoration of business processes after an emergency, but unlike the BCP, lacks procedures to ensure continuity of critical processes throughout an 
4524emergency or disruption. Development of the BRP should be coordinated with the disaster recovery plan and BCP. The BRP may be appended to the BCP.  
4525Continuity of Support Plan/IT Contingency Plan. OMB Circular A-130, Appendix III, requires the development and maintenance of continuity of support plans for general 
4526support systems and contingency plans for major applications. This planning guide considers continuity of support planning to be synonymous with IT contingency planning. 
4527Because an IT contingency plan should be developed for each major application and general support system, multiple contingency plans may be maintained within the 
4528organization’s BCP. 
4529The incident response plan focuses on information security responses to incidents affecting systems and/or networks. It establishes procedures to address cyber attacks 
4530against an organization's IT systems. These procedures are designed to enable security personnel to identify, mitigate, and recover from malicious computer incidents, such 
4531
4532
4533
4534
4535
4536
4537as unauthorized access to a system or data, denial of service, or unauthorized changes to system hardware or software. The continuity of support plan is the same as an IT 
4538contingency plan. It addresses IT system disruptions and establishes procedures for recovering a major application or general support system. It is not business process 
4539focused. The business continuity plan addresses business processes and provides procedures for sustaining essential business operations while recovering from a significant 
4540disruption. The continuity of operations plan addresses the subset of an organization's missions that are deemed most critical and procedures to sustain these functions at 
4541an alternate site for up to 30 days. 
4542
4543
4544The Criticality Survey is implemented through a standard questionnaire to gather input from the most knowledgeable people. Not all personnel that is going to be part of 
4545recovery teams is necessarily able to help in identifying critical functions of the organization.  
4546The intent of such a survey is to identify the services and systems that are critical to the organization.  
4547Having a clearly stated purpose for the survey helps in avoiding misinterpretations.  
4548Management's approval of the survey should be obtained before distributing it. 
4549
4550
4551DR and BCP - The keyword is ' MOST CRITICAL ' and the correct answer is ' Management Support ' as the management must be convinced of its necessity and that's why 
4552a business case must be made. The decision of how a company should recover from any disaster is purely a business decision and should be treated as so. 
4553
4554
45555.B Determine security strategies for availability and recovery 
45565.B.1 Identify solutions (e.g. cold, warm, hot, insource, outsource) 
4557A Hot Site contains everything needed to become operational in the shortest amount of time. 
4558According to the OIG, a hot site is defined as a fully configured site with complete customer required hardware and software provided by the service provider.  A hot site in 
4559the context of the CBK is always a RENTAL place.  If you have your own site fully equipped that you make use of in case of disaster that would be called a redundant site or 
4560an alternate site.  
4561Wikipedia: "A hot site is a duplicate of the original site of the organization, with full computer systems as well as near-complete backups of user data." A hot site is a 
4562duplicate of the original site of the organization, with full computer systems as well as near-complete backups of user data. Real time synchronization between the two sites 
4563may be used to completely mirror the data environment of the original site using wide area network links and specialized software. Following a disruption to the original 
4564site, the hot site exists so that the organization can relocate with minimal losses to normal operations. Ideally, a hot site will be up and running within a matter of hours or 
4565even less. Personnel may still have to be moved to the hot site so it is possible that the hot site may be operational from a data processing perspective before staff has 
4566relocated. The capacity of the hot site may or may not match the capacity of the original site depending on the organizations requirements. This type of backup site is the 
4567most expensive to operate. Hot sites are popular with organizations that operate real time processes such as financial institutions, government agencies and ecommerce 
4568providers 
4569
4570
4571A warm site has some basic equipment or in some case almost all of the equipment but it is not sufficient to be operational without bringing in the last backup and in 
4572some cases more computers and other equipment. A warm site is a location where the organisation can relocate to after the disruption that is already stocked with 
4573
4574
4575
4576
4577
4578
4579
4580
4581computer hardware similar to that of the original site, but does not contain backed up copies of data and information. It may or may not have the same capacity as the 
4582original site depending on the organisations requirements. Data will have to be restored onto the equipment at this site before activities can re-commence. 
4583
4584
4585A cold site has basically power, HVAC, basic cabling, but no or little as far as processing equipment is concerned. All other equipment must be brought to this site. It 
4586might take a week or two to reconstruct. A cold site is the most inexpensive type of backup site for an organization to operate. It does not include backed up copies of data 
4587and information from the original location of the organisation, nor does it include hardware already set up. The lack of hardware contributes to the minimal startup costs of 
4588the cold site, but requires additional time following the disaster to have the operation running at a capacity close to that prior to the disaster. 
4589
4590
4591A rolling hot-site is fully configured with all the required hardware. 
4592
4593
4594Redundant - Usually within most certification body of knowledge the terms Cold, Warm, and Hot sites refer to rental places. 
4595A synonym for Redundant site would also be Alternate Side. 
4596
4597
4598A reciprocal agreement between two companies with like equipments and processing needs provides an inexpensive alternative to other off-site facilities. 
4599Sometimes though this solution can prove to be inadequate since environments tend to be maxed out, or one site upgrades part of the equipment into something that is 
4600not necessarily compatible. As opposed to agreements with off-site facilities providers, reciprocal agreements cannot be enforced, so there is no guarantee that this facility 
4601will really be available to the company in a time of need. 
4602
4603
4604Mobile Sites are self-contained, transportable shells custom-fitted with specific telecommunications and system equipment necessary to meet system requirements. 
4605
4606
4607Mirrored Sites are fully redundant facilities with automated real-time information mirroring. Mirrored sites are identical to the primary site in all technical respects. 
4608
4609
4610Disaster Recovery should never be considered a discretionary expense. It is far too important a task. In order to maintain the continuity of the business Disaster Recovery 
4611should be a commitment of and by the organization. 
4612A discretionary fixed cost has a short future planning horizon—under a year. These types of costs arise from annual decisions of management to spend in specific fixed cost 
4613areas, such as marketing and research.  
4614A committed fixed cost has a long future planning horizon— more than on year. These types of costs relate to a company’s investment in assets such as facilities and 
4615equipment. Once such costs have been incurred, the company is required to make future payments. 
4616
4617
46185.B.2 Define processing agreement requirements (e.g. recipricol, mutual, cloud, outsourcing, virtualization) 
46195.B.3 Establish recovery time objectives and recovery point objectives 
4620
4621
4622
4623
4624
4625
4626
4627
4628The recovery point objective (RPO) is the maximum acceptable level of data loss following an unplanned “event”, like a disaster (natural or man-made), act of crime or 
4629terrorism, or any other business or technical disruption that could cause such data loss. The RPO represents the point in time, prior to such an event or incident, to which 
4630lost data can be recovered (given the most recent backup copy of the data).  
4631The point in time recovered data must meet for critical processes. 
4632In information security, criticality not only affects how long can one afford to be without a process or service ( MTD), but also when restoring data onto a recovered system, 
4633how old can the data be?  
4634For a high risk system such as banking system, the RPO can be very short with the goal of no data loss. 
4635For example, if I electronically deposit my pay check into a bank Tuesday morning at 11:23 and the bank experiences a disaster that affects the data, I would be very upset if 
4636they only did nightly backups and were only able to make my account look like it did the night before I made my deposit. 
4637While I might be able to afford the banks closure for a day or two (MTD = 24-48 hours), I would hope that the RPO (in this example no data loss) was respected. 
4638
4639
4640The recovery time objective (RTO) is a period of time within which business and / or technology capabilities must be restored following an unplanned event or disaster. The 
4641RTO is a function of the extent to which the interruption disrupts normal operations and the amount of revenue lost per unit of time as a result of the disaster.  
4642These factors in turn depend on the affected equipment and application(s). Both of these numbers represent key targets that are set by key businesses during business 
4643continuity and disaster recovery planning; these targets in turn drive the technology and implementation choices for business resumption services, backup / recovery / 
4644archival services, and recovery facilities and procedures.  
4645Many organizations put the cart before the horse in selecting and deploying technologies before understanding the business needs as expressed in RPO and RTO; IT 
4646departments later bear the brunt of user complaints that their service expectations are not being met. Defining the RPO and RTO can avoid that pitfall, and in doing so can 
4647also make for a compelling business case for recovery technology spending and staffing. 
4648Time allowed for recovery processes to be completed in order to meet the MTD.  
4649In our flat tire example, there was a MTD of one hour. So the plan to replace the spare tire must meet our next Metric, the RTO.  Considering that we needed some time to 
4650get to the side of the road safely, the RTO is always less than the MTD.  Also consider that when there is a report of a disaster, the first step is to confirm the incident and 
4651then do a damage assessment.  Issuing a disaster declaration” should only occur after the damage assessment has been done. 
4652NOTE: 
4653Remember not to confuse “disaster recovery,” which is associated with recovery of the ICT and infrastructure to a minimum level, with “emergency/crisis management,” 
4654which is primarily associated with the initial response, with the priority goal to protect life and contain damages 
4655In the flat tire example, where the emergency is not really over until the normal tire is restored.  Similarly, for an organization, the emergency is not over until all processes 
4656are fully reconstituted to the repaired / new primary site(s) and operating under normal service levels. 
4657
4658
4659Maximum Tolerable Downtime (MTD). The MTD represents the total amount of time the system owner/authorizing official is willing to accept for a mission/business 
4660process outage or disruption and includes all impact considerations. Determining MTD is important because it could leave contingency planners with imprecise direction on 
4661selection of an appropriate recovery method, and the depth of detail which will be required when developing recovery procedures, including their scope and content. 
4662Here are some examples of MTD values suggested by Shon Harris: 
4663
4664
4665
4666
4667
4668
4669
4670
4671NonEssential       30 Days 
4672Normal                7  Days 
4673Important           72 Hours 
4674Urgent                24 Hours 
4675Critical                 Minutes to hours 
4676
4677
46785.C Design Continuity Recovery solution 
46795.C.1 High availability, failover, resiliency (e.g. communication path diversity, paired development, pass-through network interfaces, application) 
46805.C.2 Availability of service porvidor/ supplier support (e.g. cloud, SLAs) 
46815.C.3 BCP/DRP Architecture Validation (e.g. test scenarios, requirements traceability matrix, trade-off matirces) 
4682
4683
4684After a test has been performed the most useful test results for management would be knowing what worked and what didn't so that they could correct the mistakes 
4685where needed. 
4686
4687
4688DR TEST: 
4689The structured walk-through test occurs when the functional representatives meet to review the plan in detail. This involves a thorough look at each of the plan steps, and 
4690the procedures that are invoked at that point in the plan. This ensures that the actual planned activities are accurately described in the plan. The checklist test is a method 
4691of testing the plan by distributing copies to each of the functional areas. The simulation test plays out different scenarios. The parallel test is essentially an operational test 
4692that is performed without interrupting current processing. 
4693
4694
4695BCP TEST: 
4696It is important to have ways to measure the success of the plan and tests against the stated objectives. Therefore, results must be quantitatively gauged as opposed to an 
4697evaluation based only on observation. Quantitatively measuring the results of the test involves a generic statement measuring all the activities performed during BCP, 
4698which gives the best assurance of an effective plan. Although choices A and B are also quantitative, they relate to specific areas, or an analysis of results from one 
4699viewpoint, namely the accuracy of the results and the elapsed time. 
4700
4701
4702The five types of BCP testing are: 
4703Checklist—Copies of the plan are sent to different department managers and business unit managers for review. This is a simple test and should be used in conjunction 
4704with other tests. 
4705Structured Walk-through—Team members and other individuals responsible for recovery meet and walk through the plan step-by-step to identify errors or assumptions. 
4706Simulation—This is a simulation of an actual emergency. Members of the response team act in the same way as if there was a real emergency. 
4707Parallel—This is similar to simulation testing, but the primary site is uninterrupted and critical systems are run in parallel at the alternative and primary sites. The systems 
4708are then compared to ensure all systems are in sync. 
4709
4710
4711
4712
4713
4714
4715
4716Full interruption—This test involves all facets of the company in a response to an emergency. It mimics a real disaster where all steps are performed to test the plan. 
4717Systems are shut down at the primary site and all individuals who would be involved in a real emergency, including internal and external organizations, participate in the 
4718test. This test is the most detailed, time-consuming, and expensive all of these. 
4719
4720
4721
4722
4723
4724OTHER: 
4725
4726The Disaster Recovery Manager should also be a member of the team that assisted in the development of the Disaster Recovery Plan. Senior-level management need to 
4727support the process but would not be involved with the initial process. 
4728
4729
4730The cited source mentions that three concepts are used to create a level of fault tolerance and redundancy in transaction processing. Electronic vaulting, remote 
4731journaling and database shadowing provide redundancy at the transaction level. Other techniques like on-site or off-site mirroring or disk duplexing provides 
4732redundancy at a lower level. 
4733
4734
4735RCV is the maximum amount your insurance company will pay you for damage to covered property before deducting for depreciation. The RCV payment is based on the 
4736current cost to replace your property with new, identical or comparable property.  
4737
4738
4739
4740
4741critical support  - Business units or functions that must be present to sustain continuity of business, maintain life safety and avoid public embarrassment 
4742
4743Electronic Vaulting is the process of transferring backup data to off-site location through communication lines.  
4744
4745Remote Journaling is a higher level of transaction redundancy than Electronic Vaulting. Remote Journaling is a technology to facilitate sending copies of the journal of 
4746transaction entries from a production system to a secondary system in realtime. The remote nature of such a connection is predicated upon having local journaling already 
4747established. Local journaling on the production side allows each change that ensues for a journal-eligible object e.g., database physical file, SQL table, data area, data 
4748queue, byte stream file residing within the IFS) to be recorded and logged. It’s these local images that flow to the remote system. Once there, the journal entries serve a 
4749variety of purposes, from feeding a high availability software replay program or data warehouse to offering an offline, realtime vault of the most recent database changes. 
4750
4751
4752
4753
4754The least critical functions should be moved back first 
4755
4756It's interesting to note that the steps to resume normal processing operations will be different than the steps of the recovery plan; that is, the least critical work should be 
4757brought back first to the primary site. 
4758
4759
4760
4761
4762
4763
4764
4765The most important point above in the steps would be to move the least critical items or resources back to the primary site first. This way you can ensure that the site was 
4766really well prepared and that all is working fine. 
4767
4768Before that first step would be done, you would get the green light from the salvage team that it is fine to move back to the primary site. The first step after getting the 
4769green light would be to move the least critical elements first. 
4770
4771
4772RAID Level 2 :- The parity information is created using a hamming code that detects errors and establishes which part of which drive is in error. 
4773
4774The correct answer is ' Critical recovery priority levels are not defined ' as the lack of definition of critical recovery priority levels would damage the recovery 
4775timeframe window, since this would cause applications to be recovered that might not be needed for the critical process. 
4776
4777
4778
4779
4780
4781Mean-time-between failure (MTBF) is the average length of time the hardware is functional without failure.  
4782Mean-time-to-repair is the amount of time it takes to repair and resume normal operation after a failure has occurred. 
4783Having a higher MTBF and a lower MTTR will increase the reliability of a piece of equipment, thus the system's overall reliability. 
4784
4785
4786ROLES: 
4787Many elements of a BCP will address senior management, such as the statement of importance and priorities, the statement of organizational responsibility, and the 
4788statement of urgency and timing. Executive management staff initiates the project, gives final approval and gives ongoing support. The BCP committee directs the planning, 
4789implementation, and tests processes whereas functional business units participate in implementation and testing. 
4790The BCP committee should be made up of at least the following: 
4791•   Business Units 
4792•   Senior Management 
4793•   IT Department 
4794•   Security Department 
4795•   Communications Department 
4796•   Legal Department  
4797The HR department is not included in this list and does not necessarily have to be a part of the BCP committee. 
4798
4799
4800Electronic vaulting refers to the transfer of backup data to an off-site location. This is primarily a batch process of dumping backup data through communications lines to 
4801a server at an alternate location. Remote journaling refers to the parallel processing of transactions to an alternate site (as opposed to a batch dump process). Database 
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811shadowing uses the live processing of remote journaling, but creates even more redundancy by duplicating the database sets to multiple servers. Data clustering refers to 
4812the classification of data into groups (clusters). 
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
48646 Physical security considerations 
4865
48666.A Assess requirements 
48676.A.1 Policies and standards (e.g. export controls, escort policy, liase with law enforcement and external media) 
48686.A.2 Intergrate physical security with identity (e.g. wiring closet access, badge and enterprise identity management) 
48696.A.3 Map physical security needs against business drivers (e.g. outsourcing, relocations, mergers, acquisitions, divestitures, plant closings) 
4870
4871
48726.B Integrate Physical Products and Systems 
48736.B.1 Review common techniques, technologies and architectural principles 
4874
4875
4876A Class C fire extinguisher is preferable when a fire involves electrical equipment including wiriing. Common Class C suppression includes: gas (i.e. Halon, FM-200, Carbon 
4877Dioxide, etc) or soda acid. 
4878To aid in memorization of Fire Class write on a paper the classes A through D, simply think of my firstname which is CLEMENT then put the word CLEM vertically as shown 
4879below:  
4880Class A -> C = Combustible 
4881Class B -> L = Liquid  
4882Class C -> E = Electrical  
4883Class D -> M = Metals  
4884Below you will find a more detailed model.  
4885Class A = Combustible 
4886Type of Fire: Common Combustibles 
4887Elements of Fire: wood products, paper, and laminates 
4888Suppression Method: water, foam 
4889Class B = Liquid 
4890Type of Fire: Liquid 
4891Elements of Fire: Petroleum products and coolants 
4892Suppression Method: Gas, CO2, foam, dry powders.  
4893Class C = Electrical 
4894Type of Fire: Electrical 
4895Elements of Fire: Electrical equipment and wires 
4896Suppression Method: Gas, CO2, dry powders. 
4897Class D = Metals 
4898Type of Fire: Combustible Metals 
4899Elements of Fire: Magnesium, sodium, potassium 
4900
4901
4902
4903
4904
4905
4906Suppression Method: Dry powder. 
4907
4908
4909Halon - It must be noted that Halon is now banned from being produce or manufacture in most country or cities. 
4910Multiple countries have agreed to and signed The Montreal Protocol which disallow production of Halon. 
4911Data Centers that still have Halon loaded within their cylinders will replace it with a safe replacement such as FM200 or Innergen if they ever make use of it. 
4912Halon is a compound consisting of bromine, fluorine, and carbon.  Halons are used as fire extinguishing agents, both in built-in systems and in handheld portable fire 
4913extinguishers. Halon production in the U.S. ended on December 31, 1993, because they contribute to ozone depletion.  Bromine being part of Halon is not a safe 
4914replacement for Halon.    
4915Halon replacement: 
4916Innergen, 
4917FM200 
4918FE13 
4919The correc answer is:  Order a non-Hydrochlorofluorocarbon compound from the manufacturer 
4920The best choice is to find or replace the systems with a Non-Hydrochlorofluorocarbon compound.  A safe replacement such as Innergen, FM-200, or other non ozone 
4921depleting agent would be used.    
4922
4923
4924Four elements must be presentin order for fire to exist. These elements are HEAT, FUEL, OXYGEN and CHAIN REACTION.  
4925While not everything is known about the combustion process, it is generally accepted that fire is a chemical  reaction.  This reaction is dependent upon a material rapidly 
4926oxidizing, or uniting with oxygen so rapidly that it produces heat and flame.  
4927Until the advent of newer fire extinguishing agents, fire was thought of as a triangle with the three sides represented by heat, fuel, and oxygen.  If any one of the three sides 
4928were to be taken away, the fire would cease to exist.  
4929Studies of modern fire extinguishing agents have revealed a fourth element - a self propagating chain reaction in the combustion process. As a result, the basic elements of 
4930fire are represented by the fire tetrahedron - HEAT, FUEL, OXYGEN and CHAIN REACTION.  
4931The theory of fire extinguishment is based on removing any one or more of the four elements in the fire tetrahedron to suppress the fire.  
4932
4933
4934REMOVING THE HEAT  
4935In order to remove the heat, something must be applied to the fire to absorb the heat or act as a heat exchanger. Water is not the only agent used to accomplish this, but it 
4936is the most common.  
4937
4938
4939REMOVING THE FUEL  
4940Under many circumstances, it is not practical to attempt to remove the fuel from the fire.  When dealing with flammable liquid fires, valves can be shut off and storage 
4941vessels pumped to safe areas to help eliminate the supply of fuel to the fire. Flammable gas fires are completely extinguished by shutting off the fuel supply.  
4942
4943
4944REMOVE THE OXYGEN  
4945
4946
4947
4948
4949
4950
4951Oxygen as it exists in our atmosphere (21%) is sufficient to support combustion in most fire situations. Removal of the air or oxygen can be accomplished by separating it 
4952from the fuel source or by displacing it with an inert gas. Examples of separation would be  foam on a flammable liquid fire, a wet blanket on a trash fire, or a tight fitting lid 
4953on a skillet fire.  Agents such as CO2, nitrogen, and steam are used to displace the oxygen.  
4954
4955
4956INTERRUPT THE CHAIN REACTION  
4957Modern extinguishing agents, such as dry chemical and halons, have proven to be effective on various fires even though these agents do not remove heat, fuel, or oxygen.  
4958Dry chemical and halogenated agents are thought to suspend or bond with “free radicals” that are created in the combustion process and thus prevent them from 
4959continuing the chain reaction. 
4960
4961
4962UPSs use battery packs that range in size and capacity. A UPS can be online or standby.  
4963Online UPS systems use AC line voltage to charge a bank of batteries. When in use, the UPS has an inverter that changes the DC output from the batteries into the required 
4964AC form and that regulates the voltage as it powers computer devices.  
4965Online UPS systems have the normal primary power passing through them day in and day out. They constantly provide power from their own inverters, even when the 
4966electric power is in proper use. Since the environment's electricity passes through this type of UPS all the time, the UPS device is able to quickly detect when a power failure 
4967takes place. An online UPS can provide the necessary electricity and picks up the load after a power failure much more quickly than a standby UPS.  
4968Standby UPS devices stay inactive until a power line fails. The system has sensors that detect a power failure, and the load is switched to the battery pack. The switch to the 
4969battery pack is what causes the small delay in electricity being provided.  
4970So an online UPS picks up the load much more quickly than a standby UPS, but costs more of course. 
4971
4972
4973A dry pipe system is used in areas where the water in the pipes is subject to freezing, and to minimize the chances of accidental discharge of water if the pipes would freeze 
4974in the winter time, and It minimizes chances of accidental discharge of water as well by not releasing the water until the pressure in the pipe would drop due to one of the 
4975sprinkler head being opened.  
4976A Dry Pipe system has the water being held back from charging the sprinkler pipe system by a special kind of check valve called a "dry pipe valve" or "clapper valve".   A dry 
4977pipe system is also a system which the pipes are filled with pressurized air or nitrogen rather than water. The air uses a mechanical advantage which holds back a device 
4978known as a dry pipe valve or clapper valve that prevent the water from getting into the pipe when it is pressurized.  A small amount of water, called priming water, is also 
4979inside the dry pipe system, which is filled with either air or nitrogen under pressure. 
4980The sprinkler pipe system is filled with pressurized air or nitrogen, which keeps the dry pipe valve closed using mechanical advantage.  When any of the sprinkler valves 
4981open, the pressurized air or nitrogen is released, and the dropping pressure permits the dry pipe valve to open. It's primary use is to protect the sprinkler pipes from 
4982freezing. 
4983A Wet Pipe system has the pipes always charged with water, and the thermal-fusible link in each sprinkler head is holding back the water.  If any sprinkler head is exposed 
4984to enough heat, for long enough, the link will break/melt and water will be discharged.  A wet pipe system is generally used when there is no danger of the water in the 
4985pipes freezing or when there are no special conditions that require a special purpose sprinkler system. 
4986A Preaction Pipe system is used where accidental activation is undesired. It is similar to a Dry Pipe system, except one or more other interlocks, such as fire/heat sensors, 
4987are used in addition to sprinkler head opening and relieving the air pressure, which then permits the water to charge the sprinkler pipe system and flow through the open 
4988
4989
4990
4991
4992
4993
4994sprinkler head. This system has the added value of requiring a series of events before the water is actually permitted to flow, which can enable personnel to handle a small 
4995fire or incident without the flow of water. Preaction systems are similar to dry pipe systems in that the water is not held in the pipes, but is released when the pressurized 
4996air within the pipes is reduced. Once this happens, the pipes are filled with water, but it is not released right away. A thermal-fusible link on the sprinkler head has to melt 
4997before the water is released. The purpose of combining these two techniques is to give people more time to respond to false alarms or to small fires that can be handled by 
4998other means. Putting out a small fire with a handheld extinguisher is better than losing a lot of electrical equipment to water damage. These systems are usually used only 
4999in data processing environments rather than the whole building, because of the higher cost of these types of systems. 
5000Deluge A deluge system has its sprinkler heads wide open to allow a larger volume of water to be released in a shorter period. Because the water being released is in such 
5001large volumes, these systems are usually not used in data processing environments. 
5002
5003
50046.B.2 Perimeter protection and internal zoning 
5005
5006
5007Power Excess 
5008Spike  --> Too much voltage for a short period of time.  
5009Surge --> Too much voltage for a long period of time.  
5010
5011
5012Power Loss  
5013Fault      --> A momentary power outage.  
5014Blackout --> A long power interruption.  
5015
5016
5017Power Degradation  
5018Sag or Dip  --> A momentary low voltage.  
5019Brownout   --> A prolonged power supply that is below normal voltage.   
5020
5021
50226.C Evaluate Solutions 
50236.C.1 Define test scenarios 
50246.C.2 Evaluate test deficiencies 
5025
5026
5027
5028OTHER: 
5029Electrical distribution systems 
5030When you consider top priority tickets for the data center, security, data protection, and power consumption rise to the top. But the one thing that every data center 
5031should have, that we often throw on the back burner, is fire protection.  Right now, if you heard that your data center was engulfed in flames, you would likely sit in shock, 
5032especially if you were not equipped with the proper protection. Fortunately, you can avoid this reality by taking the proper steps to protect your data center.  
5033
5034
5035
5036
5037
5038
5039
5040Dave Admirand, chief data center engineer at PTS Data Center Solutions (www.ptsdcs.com), says in his own experience, electrical fires are the most common types of fires 
5041in data centers. He says, "These are typically caused by electronic equipment failures or failures of the branch circuits powering the data center equipment, including UPS 
5042and air-conditioning equipment—if located in the data center.” 
5043So what does the industry offer when it comes to fire detectors and extinguishing systems designed for the data center? According to Ziemba, there is a myriad of different 
5044smoke and heat detectors available, and some, he says, are so sophisticated that they can detect—and help extinguish—a fire even before it reaches the incipient, or flame, 
5045stage. He says, “Detectors that provide early warning capabilities are very effective in this type of situation. Addressable control panels serve as the brains for the overall 
5046fire suppression system in that they receive the signals from the detectors, provide some type of warning to the occupants, and then discharge the system.” 
5047
5048
5049SENSORS: 
5050These types of sensors are designed for indoor use. Outdoor use would not be advised due to false alarm vulnerability and weather durability. 
5051Passive infrared detectors 
5052The passive infrared detector (PIR) is one of the most common detectors found in household and small business environments because it offers affordable and reliable 
5053functionality. The term passive means the detector is able to function without the need to generate and radiate its own energy (unlike ultrasonic and microwave volumetric 
5054intrusion detectors that are “active” in operation).  PIRs are able to distinguish if an infrared emitting object is present by first learning the ambient temperature of the 
5055monitored space and then detecting a change in the temperature caused by the presence of an object.  Using the principle of differentiation, which is a check of presence 
5056or nonpresence, PIRs verify if an intruder or object is actually there. Creating individual zones of detection where each zone comprises one or more layers can achieve 
5057differentiation.  Between the zones there are areas of no sensitivity (dead zones) that are used by the sensor for comparison. 
5058
5059
5060Ultrasonic detectors 
5061Using frequencies between 15 kHz and 75 kHz, these active detectors transmit ultrasonic sound waves that are inaudible to humans.  The Doppler shift principle is the 
5062underlying method of operation, in which a change in frequency is detected due to object motion.  This is caused when a moving object changes the frequency of sound 
5063waves around it.  Two conditions must occur to successfully detect a Doppler shift event: 
5064There must be motion of an object either towards or away from the receiver.The motion of the object must cause a change in the ultrasonic frequency to the receiver 
5065relative to the transmitting frequency.The ultrasonic detector operates by the transmitter emitting an ultrasonic signal into the area to be protected. The sound waves are 
5066reflected by solid objects (such as the surrounding floor, walls and ceiling) and then detected by the receiver. Because ultrasonic waves are transmitted through air, then 
5067hard-surfaced objects tend to reflect most of the ultrasonic energy, while soft surfaces tend to absorb most energy. 
5068When the surfaces are stationary, the frequency of the waves detected by the receiver will be equal to the transmitted frequency.  However, a change in frequency will 
5069occur as a result of the Doppler principle, when a person or object is moving towards or away from the detector. Such an event initiates an alarm signal.  This technology is 
5070considered obsolete by many alarm professionals, and is not actively installed. 
5071
5072
5073Microwave detectors 
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084This device emits microwaves from a transmitter and detects any reflected microwaves or reduction in beam intensity using a receiver.  The transmitter and receiver are 
5085usually combined inside a single housing (monostatic) for indoor applications, and separate housings (bistatic) for outdoor applications. To reduce false alarms this type of 
5086detector is usually combined with a passive infrared detector or "Dualtec" alarm. 
5087Microwave detectors respond to a Doppler shift in the frequency of the reflected energy, by a phase shift, or by a sudden reduction of the level of received energy. Any of 
5088these effects may indicate motion of an intruder. 
5089
5090
5091Photo-electric beams 
5092Photoelectric beam systems detect the presence of an intruder by transmitting visible or infrared light beams across an area, where these beams may be obstructed. To 
5093improve the detection surface area, the beams are often employed in stacks of two or more.  However, if an intruder is aware of the technology's presence, it can be 
5094avoided.  The technology can be an effective long-range detection system, if installed in stacks of three or more where the transmitters and receivers are staggered to 
5095create a fence-like barrier. Systems are available for both internal and external applications.  To prevent a clandestine attack using a secondary light source being used to 
5096hold the detector in a 'sealed' condition whilst an intruder passes through, most systems use and detect a modulated light source. 
5097
5098
5099Glass break detectors 
5100The glass break detector may be used for internal perimeter building protection. When glass breaks it generates sound in a wide band of frequencies. These can range from 
5101infrasonic, which is below 20 hertz (Hz) and can not be heard by the human ear, through the audio band from 20 Hz to 20 kHz which humans can hear, right up to 
5102ultrasonic, which is above 20 kHz and again cannot be heard. Glass break acoustic detectors are mounted in close proximity to the glass panes and listen for sound 
5103frequencies associated with glass breaking. Seismic glass break detectors are different in that they are installed on the glass pane. When glass breaks it produces specific 
5104shock frequencies which travel through the glass and often through the window frame and the surrounding walls and ceiling. Typically, the most intense frequencies 
5105generated are between 3 and 5 kHz, depending on the type of glass and the presence of a plastic interlayer. Seismic glass break detectors “feel” these shock frequencies 
5106and in turn generate an alarm condition. 
5107The more primitive detection method involves gluing a thin strip of conducting foil on the inside of the glass and putting low-power electrical current through it. Breaking 
5108the glass is practically guaranteed to tear the foil and break the circuit. 
5109
5110
5111Smoke, heat, and carbon monoxide detectors   
5112Most systems may also be equipped with smoke, heat, and/or carbon monoxide detectors. These are also known as 24 hour zones (which are on at all times). Smoke 
5113detectors and heat detectors protect from the risk of fire and carbon monoxide detectors protect from the risk of carbon monoxide. Although an intruder alarm panel may 
5114also have these detectors connected, it may not meet all the local fire code requirements of a fire alarm system. 
5115
5116
5117Other types of volumetric sensors could be:  
5118Active Infrared 
5119Passive Infrared/Microware combined 
5120Radar 
5121Accoustical Sensor/Audio 
5122
5123
5124
5125
5126
5127
5128Vibration Sensor (seismic) 
5129Air Turbulence  
5130
5131
5132EMI 
5133Common-mode noise is electrical noise between the hot and ground wire and between the neutral and ground wire. 
5134Common mode noise will disrupt the memory logic of the processor. Noise between neutral and ground creates problems since the theoretical zero voltage between 
5135neutral and ground is utilized by microprocessors and digital logic control systems as zero voltage reference. A voltage on the ground wire will disrupt the stored memory 
5136variables of today's fast microprocessors. Common mode noise can be incorrectly interpreted as data.  
5137This noise can cause what appears to be "software glitches", erratic performance of the equipment and partial or complete memory loss. Poor grounding also contributes 
5138significantly to common mode noise and this dynamic situation can change with building age, material corrosion, soil conditions and construction. 
5139
5140
5141Crime Prevention Through Environmental Design (CPTED) is a discipline that outlines how the proper design of a physical environment can reduce crime by directly 
5142affecting human behavior. It provides guidance about lost and crime prevention through proper facility contruction and environmental components and procedures. 
5143Crime prevention through Environmental Design (CPTED) is a concept that encourages individuals to feel ownership and respect for the territory they consider occupy. By 
5144encouraging the use of physical attributes that express ownership, the individual is more apt to protect and be aware in that environment 
5145The three main components of CPTED are:  
51461) natural access control - the guidance of people entering and leaving a space by the placement of doors, fences, lighting, and even landscaping  
51472) natural surveillance - the goal is make criminals feel uncomfortable by providing many ways observers could potentially see them  
51483) natural territorial reinforcement - creates physical designs that emphasize or extend the company's physical sphere of influence so users feel a sense of ownership of that 
5149space.   
5150
5151
5152Positive pressurization means that when an employee opens a door, the air goes out and outside air does not come in. 
5153
5154
5155In  building construction, a plenum (pronounced PLEH-nuhm, from Latin meaning full) is a separate space provided for air circulation for heating, ventilation, and air- 
5156conditioning (sometimes referred to as HVAC) and typically provided in the space between the structural ceiling and a drop-down ceiling. A plenum may also be under a 
5157raised floor. In buildings with computer installations, the plenum space is often used to house connecting communication cables. Because ordinary cable introduces a toxic 
5158hazard in the event of fire, special plenum cabling is required in plenum areas. 
5159
5160
5161DATA CENTRE LOCATION 
5162You data center should be located in the middle of the facility or the core of a building to provide protection from natural disasters or bombs and provide easier access to 
5163emergency crewmembers if necessary.  By being at the core of the facility the external wall would act as a secondary layer of protection as well.  
5164Information processing facilities should not be located on the top floors of buildings in case of a fire or flooding coming from the roof.  Many crimes and theft have also 
5165been conducted by simply cutting a large hole on the roof.  
5166
5167
5168
5169
5170
5171
5172
5173They should not be in the basement because of flooding where water has a natural tendancy to flow down :-)  Even a little amount of water would affect your operation 
5174considering the quantity of electrical cabling sitting directly on the cement floor under under your raise floor.   
5175The data center should not be located on the first floor due to the presence of the main entrance where people are coming in and out.  You have a lot of high traffic areas 
5176such as the elevators, the loading docks,  cafeteria, coffee shopt, etc..  Really a bad location for a data center. 
5177So it was easy to come up with the answer by using the process of elimination where the top, the bottom, and the basement are all bad choices.  That left you with only one 
5178possible answer which is the third floor. 
5179
5180
5181Capacitance detectors monitor an electrical field surrounding the object being monitored. They are used for spot protection within a few inches of the object, rather than 
5182for overall room security monitoring used by wave detectors. Penetration of this field changes the electrical capacitance of the field enough to generate and alarm. Wave 
5183pattern motion detectors generate a frequency wave pattern and send an alarm if the pattern is disturbed as it is reflected back to its receiver. Field-powered devices are a 
5184type of personnel access control devices. Audio detectors simply monitor a room for any abnormal sound wave generation and trigger an alarm. 
5185
5186
5187Integrity Controls Mechanisms are not part of physical security.  All of the other detractors were correct this one was the wrong one that does not belong to Physical 
5188Security.  Below you have more details extracted from the SearchSecurity web site:  
5189Information security depends on the security and management of the physical space in which computer systems operate. Domain 9 of the CISSP exam's Common Body of 
5190Knowledge addresses the challenges of securing the physical space, its systems and the people who work within it by use of administrative, technical and physical controls. 
5191The following topics are covered:  
5192•   Facilities management: The administrative processes that govern the maintenance and protection of the physical operations space, from site selection through 
5193    emergency response. 
5194•   Risks, issues and protection strategies: Risk identification and the selection of security protection components.  
5195•   Perimeter security: Typical physical protection controls. 
5196
5197
5198
5199
5200
5201The effectiveness of security controls is measured by the probability of detection at the point where there is enough time for a response team to interrupt an adversary. 
5202The critical path is the adversary path with the lowest probability of interruption. 
5203An adversary path is an ordered sequence of actions against an asset that could result in it being compromised. Adversaries could normally be expected to take the easiest 
5204and most direct route.  Early detection of unauthorised access enables a quicker response. Ideally interception should occur before access to the asset, but this depends on 
5205the asset and the security objectives. Interruption may not be required if tamper evidence is the objective for protecting the asset. 
5206
5207
5208The ideal operating humidity range is defined as 40 percent to 60 percent. High humidity: 
5209(greater than 60 percent) can produce - Corrosion. 
5210(less than 40 percent) can produce – Static Electricity 
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220Lighting should be used to discourage intruders and provide safety for personnel, entrances, parking areas and critical sections. Critical areas should be illuminated 8 feet 
5221high and 2 feet out. 
5222
5223
5224Magnetic media are affected from 100 degrees Fahrenheit. Disks are damaged at 150 degrees Fahrenheit, computer equipment at 175 degrees Fahrenheit, and paper 
5225products at 350 degrees Fahrenheit. 
5226
5227
5228A static charge of 1500 volts is able to cause disk drive data loss. 
5229A charge of 1000 volts is likely to scramble monitor display and a charge of 2000 volts can cause a system shutdown.  
5230It should be noted that charges of up to 20,000 volts or more are possible under conditions of very low humidity with non-static-free carpeting. 
5231
5232
5233
5234FAIL? 
5235Fail soft 
5236A system that experience a security issue would disable only the portion of the system being affected by the issue.  The rest of the system would continue to function as 
5237expected.  The component or service that failed would be isolated or protected from being abused.  
5238Fail Safe 
5239A fail-safe lock in the PHYSICAL security context will default to being unlocked in case of a power interruption. 
5240A fail-safe mechanisms in the LOGICAL security context will default to being locked in case of problem or issues.  For example if you have firewall and it cannot apply the 
5241policy properly, it will default to NO access and all will be locked not allowing any packet to flow through without being inspected.  
5242Fail open 
5243A Fail Open mean that the mechanism will default to being unlocked in case of a failure or problem.  This is very insecure.  If you have a door access control mechanism that 
5244fail open then it means that the door would be unlocked and anyone could get through. A logical security mechanism would grant access and do no access control. 
5245Fail closed 
5246A Fail closed mean that the mechanism will default to being locked in case of a failure or problem.   That would be a lot more secure than Fail Open for a logical access 
5247control mechanism. 
5248Fail secure 
5249A fail-secure in the logical or physical security context will default to being locked in case of a power interruption or a service that is not functioning properly.  Nobody could 
5250exit the building and nobody would be able to come in either.  In case of the logical context there is no access granted and everything is locked.