Fj77F5Wz

1/*
2 * To change this license header, choose License Headers in Project Properties.
3 * To change this template file, choose Tools | Templates
4 * and open the template in the editor.
5 */
6package javaapplication18;
7
8import java.security.Key;
9import java.security.KeyPair;
10import java.security.KeyPairGenerator;
11import java.security.Security;
12import java.security.SecureRandom;
13import javax.crypto.Cipher;
14
15import java.security.InvalidKeyException;
16import java.security.NoSuchAlgorithmException;
17import javax.crypto.BadPaddingException;
18import javax.crypto.IllegalBlockSizeException;
19import javax.crypto.NoSuchPaddingException;
20import javax.crypto.SecretKey;
21import javax.crypto.SecretKeyFactory;
22import javax.crypto.ShortBufferException;
23import javax.crypto.spec.IvParameterSpec;
24import javax.crypto.spec.PBEKeySpec;
25import javax.crypto.spec.SecretKeySpec;
26import javax.rmi.CORBA.Util;
27
28/**
29 *
30 * @author student
31 */
32public class JavaApplication18 {
33
34    /**
35     * @param args the command line arguments
36     */
37    public static SecretKey small_to_big_password(String short_pass) {
38
39        char[] password = short_pass.toCharArray();
40        byte[] salt = new byte[16];
41        int iteration_count = 10000;
42        int iterations = 100;
43        int key_size = 128;
44        long startTime = System.nanoTime();
45
46        for (int i = 0; i < iterations; i++) {
47            SecureRandom myPRNG = new SecureRandom();
48
49            SecretKey myAESPBKey = new SecretKeySpec(salt, "AES");
50            // set salt values to random         
51            myPRNG.nextBytes(salt);
52            try {
53                // initialize key factory for HMAC-SHA1 derivation 
54                SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
55                // set key specification 
56                PBEKeySpec pbekSpec = new PBEKeySpec(password, salt, iteration_count, key_size);
57                // generate the key 
58                myAESPBKey = new SecretKeySpec(keyFactory.generateSecret(pbekSpec).getEncoded(), "AES");
59            } catch (Exception e) {
60                System.out.println("A error occured in small to big password");
61                System.out.println(e);
62            }
63        }
64
65        long endTime = System.nanoTime();
66        long duration = (endTime - startTime) / (iterations * 1000000);
67
68        System.out.println("Time to calculate AESkey from small key: " + duration + " milliseconds");
69
70        SecureRandom myPRNG = new SecureRandom();
71
72        SecretKey myAESPBKey = new SecretKeySpec(salt, "AES");
73        // set salt values to random         
74        myPRNG.nextBytes(salt);
75        try {
76            // initialize key factory for HMAC-SHA1 derivation 
77            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
78            // set key specification 
79            PBEKeySpec pbekSpec = new PBEKeySpec(password, salt, iteration_count, key_size);
80            // generate the key 
81            myAESPBKey = new SecretKeySpec(keyFactory.generateSecret(pbekSpec).getEncoded(), "AES");
82        } catch (Exception e) {
83            System.out.println("A error occured in small to big password");
84            System.out.println(e);
85        }
86        // return the key 
87        return myAESPBKey;
88
89    }
90
91    public static void first_example() {
92        try {
93            byte[] keyBytes = new byte[16];
94            // declare secure PRNG 
95            SecureRandom myPRNG = new SecureRandom();
96            // seed the key 
97            myPRNG.nextBytes(keyBytes);
98            // build the key from random key bytes 
99            SecretKeySpec myKey = new SecretKeySpec(keyBytes, "AES");
100            // instantiate AES object for ECB with no padding 
101            Cipher myAES = Cipher.getInstance("AES/ECB/NoPadding");
102            // initialize AES objecy to encrypt mode 
103            myAES.init(Cipher.ENCRYPT_MODE, myKey);
104            // initialize plaintext 
105            byte[] plaintext = new byte[16];
106            //initialize ciphertext 
107            byte[] ciphertext = new byte[16];
108
109            // update cipher with the plaintext 
110            int cLength = myAES.update(plaintext, 0, plaintext.length, ciphertext, 0);
111            // process remaining blocks of plaintext 
112            cLength += myAES.doFinal(ciphertext, cLength);
113
114            // print plaintext and ciphertext 
115            System.out.println("plaintext: " + javax.xml.bind.DatatypeConverter.printHexBinary(plaintext));
116            System.out.println("ciphertext: " + javax.xml.bind.DatatypeConverter.printHexBinary(ciphertext));
117            // initialize AES for decryption 
118            myAES.init(Cipher.DECRYPT_MODE, myKey);
119            // initialize a new array of bytes to place the decryption 
120            byte[] dec_plaintext = new byte[16];
121            cLength = myAES.update(ciphertext, 0, ciphertext.length, dec_plaintext, 0);
122            // process remaining blocks of ciphertext 
123            cLength += myAES.doFinal(dec_plaintext, cLength);
124            // print the new plaintext (hopefully identical to the initial one) 
125            System.out.println("decrypted: " + javax.xml.bind.DatatypeConverter.printHexBinary(dec_plaintext));
126        } catch (Exception e) {
127            System.out.println("A error occured");
128            System.out.println(e);
129        }
130    }
131
132    public static void main(String[] args) {
133        String password = "short_password";
134//        first_example();
135        System.out.println("AES key: " + javax.xml.bind.DatatypeConverter.printHexBinary(small_to_big_password(password).getEncoded()));
136        SecretKey myAESPBKey = small_to_big_password(password);
137        try {
138            Cipher myAES = Cipher.getInstance("AES/ECB/NoPadding");
139            // initialize AES objecy to encrypt mode 
140            myAES.init(Cipher.ENCRYPT_MODE, myAESPBKey);
141
142            Cipher OFB = Cipher.getInstance("AES/OFB/NoPadding");
143            // initialize AES objecy to encrypt mode 
144            OFB.init(Cipher.ENCRYPT_MODE, myAESPBKey);
145
146            Cipher CFB = Cipher.getInstance("AES/CFB/NoPadding");
147            // initialize AES objecy to encrypt mode 
148            CFB.init(Cipher.ENCRYPT_MODE, myAESPBKey);
149            byte[] plaintext = new byte[16];
150            //initialize ciphertext 
151            byte[] ciphertext = new byte[16];
152
153            int cLength = myAES.update(plaintext, 0, plaintext.length, ciphertext, 0);
154            cLength = myAES.update(plaintext, 0, plaintext.length, ciphertext, 0);
155            // process remaining blocks of plaintext 
156            cLength += myAES.doFinal(ciphertext, cLength);
157
158            System.out.println("ciphertext after ECB: " + javax.xml.bind.DatatypeConverter.printHexBinary(ciphertext));
159// update cipher with the plaintext 
160            cLength = OFB.update(plaintext, 0, plaintext.length, ciphertext, 0);
161            // process remaining blocks of plaintext 
162            cLength += OFB.doFinal(ciphertext, cLength);
163
164            System.out.println("ciphertext after OFB: " + javax.xml.bind.DatatypeConverter.printHexBinary(ciphertext));
165            // update cipher with the plaintext 
166            cLength = CFB.update(plaintext, 0, plaintext.length, ciphertext, 0);
167            // process remaining blocks of plaintext 
168            cLength += CFB.doFinal(ciphertext, cLength);
169
170            System.out.println("ciphertext after CFB: " + javax.xml.bind.DatatypeConverter.printHexBinary(ciphertext));
171
172            System.out.println("plaintext: " + javax.xml.bind.DatatypeConverter.printHexBinary(plaintext));
173
174            
175            /* ENCRYPT AND DECRYPT WITH IV */
176            System.out.println("IV");
177            // initialize AES for decryption 
178            SecureRandom randomSecureRandom = SecureRandom.getInstance("SHA1PRNG");
179            byte[] iv = new byte[CFB.getBlockSize()];
180            randomSecureRandom.nextBytes(iv);
181            IvParameterSpec ivParams = new IvParameterSpec(iv);
182            
183            CFB = Cipher.getInstance("AES/CFB/NoPadding");
184            // initialize AES objecy to encrypt mode 
185            CFB.init(Cipher.ENCRYPT_MODE, myAESPBKey, ivParams);
186                        // update cipher with the plaintext 
187            cLength = CFB.update(plaintext, 0, plaintext.length, ciphertext, 0);
188            // process remaining blocks of plaintext 
189            cLength += CFB.doFinal(ciphertext, cLength);
190
191            System.out.println("ciphertext after CFB: " + javax.xml.bind.DatatypeConverter.printHexBinary(ciphertext));
192            
193            CFB.init(Cipher.DECRYPT_MODE, myAESPBKey, ivParams);
194            // initialize a new array of bytes to place the decryption 
195            byte[] dec_plaintext = new byte[16];
196            cLength = CFB.update(ciphertext, 0, ciphertext.length, dec_plaintext, 0);
197            // process remaining blocks of ciphertext 
198            cLength += CFB.doFinal(dec_plaintext, cLength);
199            // print the new plaintext (hopefully identical to the initial one) 
200            System.out.println("decrypted: " + javax.xml.bind.DatatypeConverter.printHexBinary(dec_plaintext));
201        } catch (Exception e) {
202            System.out.println("A error occured in main");
203            System.out.println(e);
204        }
205    }
206
207}