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1 private static IDictionary<byte, SymmetricKey> SymmetricKeys
2{
3    get
4    {
5        if (symmetricKeys == null)
6        {
7            lock (typeof(SecurityManager))
8            {
9                if (symmetricKeys == null)
10                {
11                    try
12                    {
13                        IList<SymmetricKey> result = GetSymmetricKeys();
14                        symmetricKeys = new Dictionary<byte, SymmetricKey>(result.Count);
15                        SymmetricKey lastActiveKey = null;
16                        foreach (SymmetricKey key in result)
17                        {
18                            symmetricKeys.Add(key.KeyID, key);
19                            if ((DateTime.Today <= key.DateExpired) && key.Active == true)
20                                activeKey = key;
21                            if (key.Active == true)
22                                lastActiveKey = key;
23                        }
24                        if (activeKey == null)
25                        {
26                            LogManager.LogEvent(200, "Cryptography", ExceptionMessages.events_framework_AllKeysExpired, System.Diagnostics.EventLogEntryType.Warning);
27                            if (lastActiveKey != null)
28                                activeKey = lastActiveKey;
29                            else
30                                throw new CryptographicException(ExceptionMessages.exceptions_framework_NoActiveKey);
31                        }
32                    }
33                    catch (CryptographicException)
34                    {
35                        throw;
36                    }
37                    catch (Exception ex)
38                    {
39                        throw new CryptographicException(ExceptionMessages.exceptions_framework_InitSymmetricKeysFailed, ex);
40                    }
41                }
42            }
43        }
44        return symmetricKeys;
45    }
46}
47
48public static List<SymmetricKey> GetSymmetricKeys()
49{
50    string filePath = ConfigManager.KeyFilePath;
51
52    XmlDocument xmlDoc = new XmlDocument();
53    xmlDoc.Load(filePath);
54
55    List<SymmetricKey> keys = new List<SymmetricKey>();
56    foreach (XmlNode node in xmlDoc.FirstChild.ChildNodes)
57    {
58        SymmetricKey key = new SymmetricKey(Convert.ToByte(node.Attributes["KeyID"].Value),
59                                            Encoding.ASCII.GetString(DataEncryption.DecryptSymmetric(Convert.FromBase64String(node.Attributes["Key"].Value))),
60                                            Convert.ToBoolean(node.Attributes["Active"].Value),
61                                                Convert.ToDateTime(node.Attributes["DateActivated"].Value),
62                                            Convert.ToDateTime(node.Attributes["DateExpired"].Value),
63                                            Convert.ToDateTime(node.Attributes["DateCreated"].Value),
64                                            node.Attributes["UsernameCreated"].Value);
65        keys.Add(key);
66
67    }
68    return keys;
69}
70
71public static byte[] DecryptSymmetric(byte[] cipherText)
72{
73    return DecryptByteArray(cipherText, Cryptographer.MasterKey);
74}
75
76public static byte[] DecryptByteArray(byte[] EncryptedData, string Password)
77{
78    if (Password == null)
79        throw new ArgumentNullException("Password");
80    RijndaelManaged RijndaelCipher = new RijndaelManaged();
81    byte[] result;
82    try
83    {
84        byte[] Salt = Encoding.ASCII.GetBytes(Password.Length.ToString(CultureInfo.InvariantCulture));
85        //Making of the key for decryption
86        PasswordDeriveBytes SecretKey = new PasswordDeriveBytes(Password, Salt);
87
88        //Creates a symmetric Rijndael decryptor object.
89        ICryptoTransform Decryptor = RijndaelCipher.CreateDecryptor(SecretKey.GetBytes(32), SecretKey.GetBytes(16));
90        MemoryStream memoryStream = new MemoryStream(EncryptedData);
91        //Defines the cryptographics stream for decryption.THe stream contains decrpted data
92        CryptoStream cryptoStream = new CryptoStream(memoryStream, Decryptor, CryptoStreamMode.Read);
93        byte[] PlainText = new byte[EncryptedData.Length];
94        int DecryptedCount = cryptoStream.Read(PlainText, 0, PlainText.Length);
95        memoryStream.Close();
96        cryptoStream.Close();
97        //Converting to string
98        result = new byte[DecryptedCount];
99        Array.Copy(PlainText, result, DecryptedCount);
100
101    }
102    finally
103    {
104        RijndaelCipher.Clear();
105    }
106    return result;
107
108}