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

   1 using System.Diagnostics.Contracts;
   2 // ==++==
   3 //
   4 //   Copyright (c) Microsoft Corporation.  All rights reserved.
   5 //
   6 // ==--==
   7 // <OWNER>Microsoft</OWNER>
   8 //
   9
  10 namespace System.Security.Cryptography {
  11     [System.Runtime.InteropServices.ComVisible(true)]
  12     public class RSAOAEPKeyExchangeFormatter : AsymmetricKeyExchangeFormatter {
  13         private byte[] ParameterValue;
  14         private RSA _rsaKey;
  15         private bool?  _rsaOverridesEncrypt;
  16         private RandomNumberGenerator RngValue;
  17
  18         //
  19         // public constructors
  20         //
  21
  22         public RSAOAEPKeyExchangeFormatter() {}
  23         public RSAOAEPKeyExchangeFormatter(AsymmetricAlgorithm key) {
  24             if (key == null)
  25                 throw new ArgumentNullException("key");
  26             Contract.EndContractBlock();
  27             _rsaKey = (RSA) key;
  28         }
  29
  30         //
  31         // public properties
  32         //
  33
  34         /// <internalonly/>
  35         public byte[] Parameter {
  36             get {
  37                 if (ParameterValue != null)
  38                     return (byte[]) ParameterValue.Clone();
  39                 return null;
  40             }
  41             set {
  42                 if (value != null)
  43                     ParameterValue = (byte[]) value.Clone();
  44                 else
  45                     ParameterValue = null;
  46             }
  47         }
  48
  49         /// <internalonly/>
  50         public override String Parameters {
  51             get { return null; }
  52         }
  53
  54         public RandomNumberGenerator Rng {
  55             get { return RngValue; }
  56             set { RngValue = value; }
  57         }
  58
  59         //
  60         // public methods
  61         //
  62
  63         public override void SetKey(AsymmetricAlgorithm key) {
  64             if (key == null)
  65                 throw new ArgumentNullException("key");
  66             Contract.EndContractBlock();
  67             _rsaKey = (RSA) key;
  68             _rsaOverridesEncrypt = default(bool?);
  69         }
  70
  71         [System.Security.SecuritySafeCritical]  // auto-generated
  72         public override byte[] CreateKeyExchange(byte[] rgbData) {
  73             if (_rsaKey == null)
  74                 throw new CryptographicUnexpectedOperationException(Environment.GetResourceString("Cryptography_MissingKey"));
  75
  76             if (OverridesEncrypt) {
  77                 return _rsaKey.Encrypt(rgbData, RSAEncryptionPadding.OaepSHA1);
  78             } else {
  79                 return Utils.RsaOaepEncrypt(_rsaKey, SHA1.Create(), new PKCS1MaskGenerationMethod(), RandomNumberGenerator.Create(), rgbData);
  80             }
  81         }
  82
  83         public override byte[] CreateKeyExchange(byte[] rgbData, Type symAlgType) {
  84             return CreateKeyExchange(rgbData);
  85         }
  86
  87         private bool OverridesEncrypt {
  88             get {
  89                 if (!_rsaOverridesEncrypt.HasValue) {
  90                     _rsaOverridesEncrypt = Utils.DoesRsaKeyOverride(_rsaKey, "Encrypt", new Type[] { typeof(byte[]), typeof(RSAEncryptionPadding) });
  91                 }
  92                 return _rsaOverridesEncrypt.Value;
  93             }
  94         }
  95     }
  96 }