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

   1 //
   2 // System.Security.Cryptography.DSA.cs class implementation
   3 //
   4 // Authors:
   5 //      Thomas Neidhart (tome@sbox.tugraz.at)
   6 //      Sebastien Pouliot (sebastien@ximian.com)
   7 //
   8 // Portions (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
   9 // Copyright (C) 2004-2005, 2008 Novell, Inc (http://www.novell.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System.Globalization;
  32 using System.Runtime.InteropServices;
  33 using System.Text;
  34
  35 using Mono.Xml;
  36 using Mono.Security;
  37
  38 // References:
  39 // a.   FIPS PUB 186-2: Digital Signature Standard (DSS)
  40 //      http://csrc.nist.gov/publications/fips/fips186-2/fips186-2-change1.pdf
  41
  42 namespace System.Security.Cryptography {
  43
  44         [ComVisible (true)]
  45         public abstract class DSA : AsymmetricAlgorithm {
  46
  47                 // Constructor visibility fixed in Fx 2.0
  48                 protected DSA ()
  49                 {
  50                 }
  51
  52                 public static new DSA Create ()
  53                 {
  54                         return Create ("System.Security.Cryptography.DSA");
  55                 }
  56
  57                 public static new DSA Create (string algName)
  58                 {
  59                         return (DSA) CryptoConfig.CreateFromName (algName);
  60                 }
  61
  62                 public abstract byte[] CreateSignature (byte[] rgbHash);
  63
  64                 public abstract DSAParameters ExportParameters (bool includePrivateParameters);
  65
  66                 internal void ZeroizePrivateKey (DSAParameters parameters)
  67                 {
  68                         if (parameters.X != null)
  69                                 Array.Clear (parameters.X, 0, parameters.X.Length);
  70                 }
  71
  72                 public override void FromXmlString (string xmlString)
  73                 {
  74                         if (xmlString == null)
  75                                 throw new ArgumentNullException ("xmlString");
  76
  77                         DSAParameters dsaParams = new DSAParameters ();
  78                         try {
  79                                 dsaParams.P = GetNamedParam (xmlString, "P");
  80                                 dsaParams.Q = GetNamedParam (xmlString, "Q");
  81                                 dsaParams.G = GetNamedParam (xmlString, "G");
  82                                 dsaParams.J = GetNamedParam (xmlString, "J");
  83                                 dsaParams.Y = GetNamedParam (xmlString, "Y");
  84                                 dsaParams.X = GetNamedParam (xmlString, "X");
  85                                 dsaParams.Seed = GetNamedParam (xmlString, "Seed");
  86                                 byte[] counter = GetNamedParam (xmlString, "PgenCounter");
  87                                 if (counter != null) {
  88                                         byte[] counter4b = new byte [4]; // always 4 bytes
  89                                         Buffer.BlockCopy (counter, 0, counter4b, 0, counter.Length);
  90                                         dsaParams.Counter = BitConverterLE.ToInt32 (counter4b, 0);
  91                                 }
  92                                 ImportParameters (dsaParams);
  93                         }
  94                         catch {
  95                                 ZeroizePrivateKey (dsaParams);
  96                                 throw;
  97                         }
  98                         finally {
  99                                 ZeroizePrivateKey (dsaParams);
 100                         }
 101                 }
 102
 103                 public abstract void ImportParameters (DSAParameters parameters);
 104
 105                 // note: using SecurityElement.ToXml wouldn't generate the same string as the MS implementation
 106                 public override string ToXmlString (bool includePrivateParameters)
 107                 {
 108                         StringBuilder sb = new StringBuilder ();
 109                         DSAParameters dsaParams = ExportParameters (includePrivateParameters);
 110                         try {
 111                                 sb.Append ("<DSAKeyValue>");
 112
 113                                 sb.Append ("<P>");
 114                                 sb.Append (Convert.ToBase64String (dsaParams.P));
 115                                 sb.Append ("</P>");
 116
 117                                 sb.Append ("<Q>");
 118                                 sb.Append (Convert.ToBase64String (dsaParams.Q));
 119                                 sb.Append ("</Q>");
 120
 121                                 sb.Append ("<G>");
 122                                 sb.Append (Convert.ToBase64String (dsaParams.G));
 123                                 sb.Append ("</G>");
 124
 125                                 sb.Append ("<Y>");
 126                                 sb.Append (Convert.ToBase64String (dsaParams.Y));
 127                                 sb.Append( "</Y>");
 128
 129                                 if (dsaParams.J != null) {
 130                                         // if J wasn't imported then it's not exported and neither
 131                                         // is part of the XML output
 132                                         sb.Append ("<J>");
 133                                         sb.Append (Convert.ToBase64String (dsaParams.J));
 134                                         sb.Append ("</J>");
 135                                 }
 136
 137                                 if (dsaParams.Seed != null) {
 138                                         sb.Append ("<Seed>");
 139                                         sb.Append (Convert.ToBase64String (dsaParams.Seed));
 140                                         sb.Append ("</Seed>");
 141
 142                                         sb.Append ("<PgenCounter>");
 143                                         // the number of bytes is important (no matter == 0x00)
 144                                         if (dsaParams.Counter != 0) {
 145                                                 byte[] inArr = BitConverterLE.GetBytes (dsaParams.Counter);
 146                                                 int l = inArr.Length;
 147                                                 while (inArr[l-1] == 0x00)
 148                                                         l--;
 149
 150                                                 sb.Append (Convert.ToBase64String (inArr, 0, l));
 151                                         } else {
 152                                                 sb.Append ("AA==");     // base64 encoded 0
 153                                         }
 154                                         sb.Append ("</PgenCounter>");
 155                                 }
 156
 157                                 if (dsaParams.X != null) {
 158                                         sb.Append ("<X>");
 159                                         sb.Append (Convert.ToBase64String (dsaParams.X));
 160                                         sb.Append ("</X>");
 161                                 }
 162                                 else if (includePrivateParameters) {
 163                                         throw new ArgumentNullException ("X");
 164                                 }
 165
 166                                 sb.Append ("</DSAKeyValue>");
 167                         }
 168                         catch {
 169                                 ZeroizePrivateKey (dsaParams);
 170                                 throw;
 171                         }
 172
 173                         return sb.ToString ();
 174                 }
 175
 176                 public abstract bool VerifySignature (byte[] rgbHash, byte[] rgbSignature);
 177         }
 178 }