mcs/class/corlib/CommonCrypto/CryptorTransform.cs

   1 // ICryptoTransform implementation on top of CommonCrypto and SymmetricTransform
   2 //
   3 // Authors:
   4 //      Sebastien Pouliot  <sebastien@xamarin.com>
   5 //
   6 // Copyright 2012 Xamarin Inc.
   7
   8 using System;
   9 using System.Security.Cryptography;
  10
  11 using Mono.Security.Cryptography;
  12
  13 namespace Crimson.CommonCrypto {
  14
  15         class CryptorTransform : SymmetricTransform {
  16
  17                 IntPtr handle;
  18                 IntPtr handle_e;
  19                 bool encryption;
  20
  21                 public CryptorTransform (IntPtr cryptor, IntPtr special, SymmetricAlgorithm algo, bool encryption, byte[] iv)
  22                         : base (algo, encryption, iv)
  23                 {
  24                         handle = cryptor;
  25                         // for CFB we need to encrypt data while decrypting
  26                         handle_e = special;
  27                         this.encryption = encryption;
  28                 }
  29
  30                 ~CryptorTransform ()
  31                 {
  32                         Dispose (false);
  33                 }
  34
  35                 // PRO: doing this ensure all cipher modes and padding modes supported by .NET will be available with CommonCrypto (drop-in replacements)
  36                 // CON: doing this will only process one block at the time, so it's not ideal for performance, but still a lot better than managed
  37                 protected override void ECB (byte[] input, byte[] output)
  38                 {
  39                         IntPtr len = IntPtr.Zero;
  40                         CCCryptorStatus s = Cryptor.CCCryptorUpdate ((encrypt == encryption) ? handle : handle_e,
  41                                 input, (IntPtr) input.Length, output, (IntPtr) output.Length, ref len);
  42                         if (((int) len != output.Length) || (s != CCCryptorStatus.Success))
  43                                 throw new CryptographicUnexpectedOperationException (s.ToString ());
  44                 }
  45
  46                 protected override void Dispose (bool disposing)
  47                 {
  48                         if (handle != IntPtr.Zero) {
  49                                 Cryptor.CCCryptorRelease (handle);
  50                                 handle = IntPtr.Zero;
  51                         }
  52                         if (handle_e != IntPtr.Zero) {
  53                                 Cryptor.CCCryptorRelease (handle_e);
  54                                 handle_e = IntPtr.Zero;
  55                         }
  56                         base.Dispose (disposing);
  57                         GC.SuppressFinalize (this);
  58                 }
  59         }
  60 }