mcs/class/referencesource/mscorlib/system/security/cryptography/rc2.cs

   1 // ==++==
   2 //
   3 //   Copyright (c) Microsoft Corporation.  All rights reserved.
   4 //
   5 // ==--==
   6 // <OWNER>[....]</OWNER>
   7 //
   8
   9 //
  10 // RC2.cs
  11 //
  12
  13 namespace System.Security.Cryptography {
  14 [System.Runtime.InteropServices.ComVisible(true)]
  15     public abstract class RC2 : SymmetricAlgorithm
  16     {
  17         protected int               EffectiveKeySizeValue;
  18         private static  KeySizes[] s_legalBlockSizes = {
  19           new KeySizes(64, 64, 0)
  20         };
  21         private static  KeySizes[] s_legalKeySizes = {
  22             new KeySizes(40, 1024, 8)  // 1024 bits is theoretical max according to the RFC
  23         };
  24
  25         //
  26         // protected constructors
  27         //
  28
  29         protected RC2() {
  30             KeySizeValue = 128;
  31             BlockSizeValue = 64;
  32             FeedbackSizeValue = BlockSizeValue;
  33             LegalBlockSizesValue = s_legalBlockSizes;
  34             LegalKeySizesValue = s_legalKeySizes;
  35         }
  36
  37         //
  38         // public properties
  39         //
  40
  41         public virtual int EffectiveKeySize {
  42             get {
  43                 if (EffectiveKeySizeValue == 0) return KeySizeValue;
  44                 return EffectiveKeySizeValue;
  45             }
  46             set {
  47                 if (value > KeySizeValue) {
  48                     throw new CryptographicException(Environment.GetResourceString("Cryptography_RC2_EKSKS"));
  49                 } else if (value == 0) {
  50                     EffectiveKeySizeValue = value;
  51                 } else if (value < 40) {
  52                     throw new CryptographicException(Environment.GetResourceString("Cryptography_RC2_EKS40"));
  53                 } else {
  54                     if (ValidKeySize(value))
  55                         EffectiveKeySizeValue = value;
  56                     else
  57                         throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKeySize"));
  58                 }
  59             }
  60         }
  61
  62         public override int KeySize {
  63             get { return KeySizeValue; }
  64             set {
  65                 if (value < EffectiveKeySizeValue) throw new CryptographicException(Environment.GetResourceString("Cryptography_RC2_EKSKS"));
  66                 base.KeySize = value;
  67             }
  68         }
  69
  70         //
  71         // public methods
  72         //
  73
  74         new static public RC2 Create() {
  75             return Create("System.Security.Cryptography.RC2");
  76         }
  77
  78         new static public RC2 Create(String AlgName) {
  79             return (RC2) CryptoConfig.CreateFromName(AlgName);
  80         }
  81     }
  82 }