mcs/class/corlib/System.Security.Cryptography/RC2.cs

   1 //
   2 // System.Security.Cryptography.RC2.cs
   3 //
   4 // Authors:
   5 //      Andrew Birkett (andy@nobugs.org)
   6 //      Sebastien Pouliot (spouliot@motus.com)
   7 //
   8
   9 using System;
  10
  11 namespace System.Security.Cryptography {
  12
  13         public abstract class RC2 : SymmetricAlgorithm {
  14
  15                 public static new RC2 Create ()
  16                 {
  17                         return Create ("System.Security.Cryptography.RC2");
  18                 }
  19
  20                 public static new RC2 Create (string algName)
  21                 {
  22                         return (RC2) CryptoConfig.CreateFromName (algName);
  23                 }
  24
  25                 protected int EffectiveKeySizeValue;
  26
  27                 public virtual int EffectiveKeySize {
  28                         get {
  29                                 if (EffectiveKeySizeValue == 0)
  30                                         return KeySizeValue;
  31                                 else
  32                                         return EffectiveKeySizeValue;
  33                         }
  34                         set {
  35                                 if (!KeySizes.IsLegalKeySize (LegalKeySizesValue, value))
  36                                         throw new CryptographicException ("key size not supported by algorithm");
  37                                 EffectiveKeySizeValue = value;
  38                         }
  39                 }
  40
  41                 // Overridden, which makes me suspect it changes effective keysize too?
  42                 public override int KeySize {
  43                         get { return KeySizeValue; }
  44                         set { KeySizeValue = value; }
  45                 }
  46
  47                 public RC2 ()
  48                 {
  49                         KeySizeValue = 128;
  50                         BlockSizeValue = 64;
  51                         FeedbackSizeValue = 64;
  52
  53                         // The RFC allows keys of 1 to 128 bytes, but MS impl only supports
  54                         // 40 to 128 bits, sigh.
  55                         LegalKeySizesValue = new KeySizes[1];
  56                         LegalKeySizesValue[0] = new KeySizes(40, 128, 8);
  57
  58                         LegalBlockSizesValue = new KeySizes[1];
  59                         LegalBlockSizesValue[0] = new KeySizes(64, 64, 0);
  60                 }
  61         }
  62 }