code.grnet.gr Git - pithos-ms-client/blob - trunk/hammock/src/netCF/Hammock.Compact/Security/Cryptography/KeyedHashAlgorithm.cs

   1 using System;
   2 using System.Security.Cryptography;
   3
   4 namespace Hammock.Security.Cryptography
   5 {
   6   public abstract class KeyedHashAlgorithm : HashAlgorithm
   7   {
   8     protected byte[] KeyValue;
   9
  10     public virtual byte[] Key
  11     {
  12       get
  13       {
  14         return (byte[])this.KeyValue.Clone();
  15       }
  16       set
  17       {
  18         if (this.State != 0)
  19         {
  20           throw new CryptographicException("Key can't be changed at this state.");
  21         }
  22
  23         this.ZeroizeKey();
  24         this.KeyValue = (byte[])value.Clone();
  25       }
  26     }
  27
  28     ~KeyedHashAlgorithm()
  29     {
  30       this.Dispose(false);
  31     }
  32
  33     protected override void Dispose(bool disposing)
  34     {
  35       this.ZeroizeKey();
  36       base.Dispose(disposing);
  37     }
  38
  39     private void ZeroizeKey()
  40     {
  41       if (this.KeyValue != null)
  42         Array.Clear(this.KeyValue, 0, this.KeyValue.Length);
  43     }
  44
  45     public static new KeyedHashAlgorithm Create()
  46     {
  47       return Create("System.Security.Cryptography.KeyedHashAlgorithm");
  48     }
  49
  50     public static new KeyedHashAlgorithm Create(string algName)
  51     {
  52       return (KeyedHashAlgorithm)CryptoConfig.CreateFromName(algName);
  53     }
  54   }
  55 }