mcs/class/referencesource/mscorlib/system/security/cryptography/rijndaelmanaged.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 //
  11 // RijndaelManaged.cs
  12 //
  13
  14 namespace System.Security.Cryptography
  15 {
  16 [System.Runtime.InteropServices.ComVisible(true)]
  17     public sealed class RijndaelManaged : Rijndael {
  18         public RijndaelManaged () {
  19 #if FEATURE_CRYPTO
  20             if (CryptoConfig.AllowOnlyFipsAlgorithms)
  21                 throw new InvalidOperationException(Environment.GetResourceString("Cryptography_NonCompliantFIPSAlgorithm"));
  22             Contract.EndContractBlock();
  23 #endif // FEATURE_CRYPTO
  24         }
  25
  26         // #CoreCLRRijndaelModes
  27         //
  28         // On CoreCLR we limit the supported cipher modes and padding modes for the AES algorithm to a
  29         // single hard coded value.  This allows us to remove a lot of code by removing support for the
  30         // uncommon cases and forcing everyone to use the same common padding and ciper modes:
  31         //
  32         //  - CipherMode: CipherMode.CBC
  33         //  - PaddingMode: PaddingMode.PKCS7
  34
  35         public override ICryptoTransform CreateEncryptor (byte[] rgbKey, byte[] rgbIV) {
  36             return NewEncryptor(rgbKey,
  37                                 ModeValue,
  38                                 rgbIV,
  39                                 FeedbackSizeValue,
  40                                 RijndaelManagedTransformMode.Encrypt);
  41         }
  42
  43         public override ICryptoTransform CreateDecryptor (byte[] rgbKey, byte[] rgbIV) {
  44             return NewEncryptor(rgbKey,
  45                                 ModeValue,
  46                                 rgbIV,
  47                                 FeedbackSizeValue,
  48                                 RijndaelManagedTransformMode.Decrypt);
  49         }
  50
  51         public override void GenerateKey () {
  52             KeyValue = Utils.GenerateRandom(KeySizeValue / 8);
  53         }
  54
  55         public override void GenerateIV () {
  56             IVValue = Utils.GenerateRandom(BlockSizeValue / 8);
  57         }
  58
  59         private ICryptoTransform NewEncryptor (byte[] rgbKey,
  60                                                CipherMode mode,
  61                                                byte[] rgbIV,
  62                                                int feedbackSize,
  63                                                RijndaelManagedTransformMode encryptMode) {
  64             // Build the key if one does not already exist
  65             if (rgbKey == null) {
  66                 rgbKey = Utils.GenerateRandom(KeySizeValue / 8);
  67             }
  68
  69             // If not ECB mode, make sure we have an IV. In CoreCLR we do not support ECB, so we must have
  70             // an IV in all cases.
  71 #if !FEATURE_CRYPTO
  72             if (mode != CipherMode.ECB) {
  73 #endif // !FEATURE_CRYPTO
  74                 if (rgbIV == null) {
  75                     rgbIV = Utils.GenerateRandom(BlockSizeValue / 8);
  76                 }
  77 #if !FEATURE_CRYPTO
  78             }
  79 #endif // !FEATURE_CRYPTO
  80
  81             // Create the encryptor/decryptor object
  82             return new RijndaelManagedTransform (rgbKey,
  83                                                  mode,
  84                                                  rgbIV,
  85                                                  BlockSizeValue,
  86                                                  feedbackSize,
  87                                                  PaddingValue,
  88                                                  encryptMode);
  89         }
  90     }
  91 }