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

   1 //
   2 // System.Security.Cryptography DSASignatureDeformatter.cs
   3 //
   4 // Authors:
   5 //      Thomas Neidhart (tome@sbox.tugraz.at)
   6 //      Sebastien Pouliot (sebastien@ximian.com)
   7 //
   8 // Portions (C) 2002 Motus Technologies Inc. (http://www.motus.com)
   9 // Copyright (C) 2004-2005 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
  34 namespace System.Security.Cryptography {
  35
  36         [ComVisible (true)]
  37         public class DSASignatureDeformatter : AsymmetricSignatureDeformatter {
  38
  39                 private DSA dsa;
  40
  41                 public DSASignatureDeformatter () : base ()
  42                 {
  43                 }
  44
  45                 public DSASignatureDeformatter (AsymmetricAlgorithm key) : base ()
  46                 {
  47                         SetKey (key);
  48                 }
  49
  50                 public override void SetHashAlgorithm (string strName)
  51                 {
  52                         if (strName == null)
  53                                 throw new ArgumentNullException ("strName");
  54
  55                         try {
  56                                 // just to test, we don't need the object
  57                                 SHA1.Create (strName);
  58                         }
  59                         catch (InvalidCastException) {
  60                                 throw new CryptographicUnexpectedOperationException (
  61                                         Locale.GetText ("DSA requires SHA1"));
  62                         }
  63                 }
  64
  65                 public override void SetKey (AsymmetricAlgorithm key)
  66                 {
  67                         if (key != null) {
  68                                 // this will throw a InvalidCastException if this isn't
  69                                 // a DSA keypair
  70                                 dsa = (DSA) key;
  71                         }
  72                         else
  73                                 throw new ArgumentNullException ("key");
  74                 }
  75
  76                 public override bool VerifySignature (byte[] rgbHash, byte[] rgbSignature)
  77                 {
  78                         if (dsa == null) {
  79                                 throw new CryptographicUnexpectedOperationException (
  80                                         Locale.GetText ("missing key"));
  81                         }
  82
  83                         return dsa.VerifySignature (rgbHash, rgbSignature);
  84                 }
  85         }
  86 }