2 // MACTripleDES.cs: Handles MAC with TripleDES
5 // Sebastien Pouliot (spouliot@motus.com)
7 // (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
11 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
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35 using Mono.Security.Cryptography;
37 namespace System.Security.Cryptography {
40 // a. FIPS PUB 81: DES MODES OF OPERATION
41 // MAC: Appendix F (MACDES not MACTripleDES but close enough ;-)
42 // http://www.itl.nist.gov/fipspubs/fip81.htm
44 // LAMESPEC: MACTripleDES == MAC-CBC using TripleDES (not MAC-CFB).
45 public class MACTripleDES: KeyedHashAlgorithm {
47 private TripleDES tdes;
48 private MACAlgorithm mac;
49 private bool m_disposed;
51 public MACTripleDES ()
53 Setup ("TripleDES", null);
56 public MACTripleDES (byte[] rgbKey)
59 throw new ArgumentNullException ("rgbKey");
60 Setup ("TripleDES", rgbKey);
63 public MACTripleDES (string strTripleDES, byte[] rgbKey)
66 throw new ArgumentNullException ("rgbKey");
67 if (strTripleDES == null)
68 Setup ("TripleDES", rgbKey);
70 Setup (strTripleDES, rgbKey);
73 private void Setup (string strTripleDES, byte[] rgbKey)
75 tdes = TripleDES.Create (strTripleDES);
76 // if rgbKey is null we keep the randomly generated key
78 // this way we get the TripleDES key validation (like weak
79 // and semi-weak keys)
82 HashSizeValue = tdes.BlockSize;
83 // we use Key property to get the additional validations
84 // (from KeyedHashAlgorithm ancestor)
86 mac = new MACAlgorithm (tdes);
95 protected override void Dispose (bool disposing)
98 // note: we ALWAYS zeroize keys (disposing or not)
100 // clear our copy of the secret key
101 if (KeyValue != null)
102 Array.Clear (KeyValue, 0, KeyValue.Length);
103 // clear the secret key (inside TripleDES)
108 // disposed managed stuff
113 base.Dispose (disposing);
118 public override void Initialize ()
121 throw new ObjectDisposedException ("MACTripleDES");
123 mac.Initialize (KeyValue);
126 protected override void HashCore (byte[] rgb, int ib, int cb)
129 throw new ObjectDisposedException ("MACTripleDES");
134 mac.Core (rgb, ib, cb);
137 protected override byte[] HashFinal ()
140 throw new ObjectDisposedException ("MACTripleDES");