class/corlib/System.Security.Cryptography/MACTripleDES.cs

   1 //
   2 // MACTripleDES.cs: Handles MAC with TripleDES
   3 //
   4 // Author:
   5 //      Sebastien Pouliot (sebastien@ximian.com)
   6 //
   7 // (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
   8 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 #if !NET_2_1 || MONOTOUCH
  31
  32 using System.Runtime.InteropServices;
  33
  34 using Mono.Security.Cryptography;
  35
  36 namespace System.Security.Cryptography {
  37
  38         // References:
  39         // a.   FIPS PUB 81: DES MODES OF OPERATION
  40         //      MAC: Appendix F (MACDES not MACTripleDES but close enough ;-)
  41         //      http://www.itl.nist.gov/fipspubs/fip81.htm
  42
  43         // LAMESPEC: MACTripleDES == MAC-CBC using TripleDES (not MAC-CFB).
  44 #if NET_2_0
  45         [ComVisible (true)]
  46 #endif
  47         public class MACTripleDES: KeyedHashAlgorithm {
  48
  49                 private TripleDES tdes;
  50                 private MACAlgorithm mac;
  51                 private bool m_disposed;
  52
  53                 public MACTripleDES ()
  54                 {
  55                         Setup ("TripleDES", null);
  56                 }
  57
  58                 public MACTripleDES (byte[] rgbKey)
  59                 {
  60                         if (rgbKey == null)
  61                                 throw new ArgumentNullException ("rgbKey");
  62                         Setup ("TripleDES", rgbKey);
  63                 }
  64
  65                 public MACTripleDES (string strTripleDES, byte[] rgbKey)
  66                 {
  67                         if (rgbKey == null)
  68                                 throw new ArgumentNullException ("rgbKey");
  69                         if (strTripleDES == null)
  70                                 Setup ("TripleDES", rgbKey);
  71                         else
  72                                 Setup (strTripleDES, rgbKey);
  73                 }
  74
  75                 private void Setup (string strTripleDES, byte[] rgbKey)
  76                 {
  77                         tdes = TripleDES.Create (strTripleDES);
  78                         // default padding (as using in Fx 1.0 and 1.1)
  79                         tdes.Padding = PaddingMode.Zeros;
  80                         // if rgbKey is null we keep the randomly generated key
  81                         if (rgbKey != null) {
  82                                 // this way we get the TripleDES key validation (like weak
  83                                 // and semi-weak keys)
  84                                 tdes.Key = rgbKey;
  85                         }
  86                         HashSizeValue = tdes.BlockSize;
  87                         // we use Key property to get the additional validations
  88                         // (from KeyedHashAlgorithm ancestor)
  89                         Key = tdes.Key;
  90                         mac = new MACAlgorithm (tdes);
  91                         m_disposed = false;
  92                 }
  93
  94                 ~MACTripleDES ()
  95                 {
  96                         Dispose (false);
  97                 }
  98
  99 #if NET_2_0
 100                 [ComVisible (false)]
 101                 public PaddingMode Padding {
 102                         get { return tdes.Padding; }
 103                         set { tdes.Padding = value; }
 104                 }
 105 #endif
 106
 107                 protected override void Dispose (bool disposing)
 108                 {
 109                         if (!m_disposed) {
 110                                 // note: we ALWAYS zeroize keys (disposing or not)
 111
 112                                 // clear our copy of the secret key
 113                                 if (KeyValue != null)
 114                                         Array.Clear (KeyValue, 0, KeyValue.Length);
 115                                 // clear the secret key (inside TripleDES)
 116                                 if (tdes != null)
 117                                         tdes.Clear ();
 118
 119                                 if (disposing) {
 120                                         // disposed managed stuff
 121                                         KeyValue = null;
 122                                         tdes = null;
 123                                 }
 124                                 // ancestor
 125                                 base.Dispose (disposing);
 126                                 m_disposed = true;
 127                         }
 128                 }
 129
 130                 public override void Initialize ()
 131                 {
 132                         if (m_disposed)
 133                                 throw new ObjectDisposedException ("MACTripleDES");
 134                         State = 0;
 135                         mac.Initialize (KeyValue);
 136                 }
 137
 138                 protected override void HashCore (byte[] rgbData, int ibStart, int cbSize)
 139                 {
 140                         if (m_disposed)
 141                                 throw new ObjectDisposedException ("MACTripleDES");
 142                         if (State == 0) {
 143                                 Initialize ();
 144                                 State = 1;
 145                         }
 146                         mac.Core (rgbData, ibStart, cbSize);
 147                 }
 148
 149                 protected override byte[] HashFinal ()
 150                 {
 151                         if (m_disposed)
 152                                 throw new ObjectDisposedException ("MACTripleDES");
 153                         State = 0;
 154                         return mac.Final ();
 155                 }
 156         }
 157 }
 158
 159 #endif
 160