mcs/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@xamarin.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 // Copyright 2013 Xamarin Inc. (http://www.xamarin.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System.Globalization;
  33 using System.Runtime.InteropServices;
  34
  35 namespace System.Security.Cryptography {
  36
  37         [ComVisible (true)]
  38         public class DSASignatureDeformatter : AsymmetricSignatureDeformatter {
  39
  40                 private DSA dsa;
  41
  42                 public DSASignatureDeformatter () : base ()
  43                 {
  44                 }
  45
  46                 public DSASignatureDeformatter (AsymmetricAlgorithm key) : base ()
  47                 {
  48                         SetKey (key);
  49                 }
  50
  51                 public override void SetHashAlgorithm (string strName)
  52                 {
  53                         if (strName == null)
  54                                 throw new ArgumentNullException ("strName");
  55
  56                         var instance = HashAlgorithm.Create (strName) as SHA1;
  57                         if (instance == null)
  58                                 throw new CryptographicUnexpectedOperationException (
  59                                         Locale.GetText ("DSA requires SHA1"));
  60                 }
  61
  62                 public override void SetKey (AsymmetricAlgorithm key)
  63                 {
  64                         if (key != null) {
  65                                 // this will throw a InvalidCastException if this isn't
  66                                 // a DSA keypair
  67                                 dsa = (DSA) key;
  68                         }
  69                         else
  70                                 throw new ArgumentNullException ("key");
  71                 }
  72
  73                 public override bool VerifySignature (byte[] rgbHash, byte[] rgbSignature)
  74                 {
  75                         if (dsa == null) {
  76                                 throw new CryptographicUnexpectedOperationException (
  77                                         Locale.GetText ("missing key"));
  78                         }
  79
  80                         return dsa.VerifySignature (rgbHash, rgbSignature);
  81                 }
  82         }
  83 }