119 lines
4.3 KiB
C#
119 lines
4.3 KiB
C#
//
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// RijndaelManaged.cs: Use CommonCrypto AES when possible,
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// fallback on RijndaelManagedTransform otherwise
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//
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// Authors:
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// Sebastien Pouliot <sebastien@xamarin.com>
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//
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// Copyright 2012 Xamarin Inc.
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//
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using System;
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using System.Security.Cryptography;
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using Mono.Security.Cryptography;
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using Crimson.CommonCrypto;
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namespace System.Security.Cryptography {
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public sealed class RijndaelManaged : Rijndael {
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public RijndaelManaged ()
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{
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}
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public override void GenerateIV ()
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{
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IVValue = KeyBuilder.IV (BlockSizeValue >> 3);
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}
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public override void GenerateKey ()
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{
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KeyValue = KeyBuilder.Key (KeySizeValue >> 3);
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}
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public override ICryptoTransform CreateDecryptor (byte[] rgbKey, byte[] rgbIV)
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{
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// AES is Rijndael with a 128 bits block size, so we can use CommonCrypto in this case
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if (BlockSize == 128) {
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IntPtr decryptor = IntPtr.Zero;
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switch (Mode) {
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case CipherMode.CBC:
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decryptor = Cryptor.Create (CCOperation.Decrypt, CCAlgorithm.AES128, CCOptions.None, rgbKey, rgbIV);
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return new FastCryptorTransform (decryptor, this, false, rgbIV);
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case CipherMode.ECB:
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decryptor = Cryptor.Create (CCOperation.Decrypt, CCAlgorithm.AES128, CCOptions.ECBMode, rgbKey, rgbIV);
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return new FastCryptorTransform (decryptor, this, false, rgbIV);
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default:
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// CFB cipher mode is not supported by the (old) API we used (for compatibility) so we fallback for them
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// FIXME: benchmark if we're better with RijndaelManagedTransform or CryptorTransform for CFB mode
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break;
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}
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}
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return NewEncryptor(rgbKey,
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ModeValue,
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rgbIV,
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FeedbackSizeValue,
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RijndaelManagedTransformMode.Decrypt);
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}
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public override ICryptoTransform CreateEncryptor (byte[] rgbKey, byte[] rgbIV)
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{
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if (BlockSize == 128) {
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IntPtr encryptor = IntPtr.Zero;
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switch (Mode) {
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case CipherMode.CBC:
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encryptor = Cryptor.Create (CCOperation.Encrypt, CCAlgorithm.AES128, CCOptions.None, rgbKey, rgbIV);
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return new FastCryptorTransform (encryptor, this, true, rgbIV);
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case CipherMode.ECB:
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encryptor = Cryptor.Create (CCOperation.Encrypt, CCAlgorithm.AES128, CCOptions.ECBMode, rgbKey, rgbIV);
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return new FastCryptorTransform (encryptor, this, true, rgbIV);
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default:
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// CFB cipher mode is not supported by the (old) API we used (for compatibility) so we fallback for them
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// FIXME: benchmark if we're better with RijndaelManagedTransform or CryptorTransform for CFB mode
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break;
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}
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}
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return NewEncryptor(rgbKey,
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ModeValue,
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rgbIV,
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FeedbackSizeValue,
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RijndaelManagedTransformMode.Encrypt);
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}
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private ICryptoTransform NewEncryptor (byte[] rgbKey,
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CipherMode mode,
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byte[] rgbIV,
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int feedbackSize,
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RijndaelManagedTransformMode encryptMode) {
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// Build the key if one does not already exist
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if (rgbKey == null) {
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rgbKey = Utils.GenerateRandom(KeySizeValue / 8);
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}
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// If not ECB mode, make sure we have an IV. In CoreCLR we do not support ECB, so we must have
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// an IV in all cases.
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#if !FEATURE_CRYPTO
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if (mode != CipherMode.ECB) {
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#endif // !FEATURE_CRYPTO
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if (rgbIV == null) {
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rgbIV = Utils.GenerateRandom(BlockSizeValue / 8);
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}
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#if !FEATURE_CRYPTO
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}
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#endif // !FEATURE_CRYPTO
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// Create the encryptor/decryptor object
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return new RijndaelManagedTransform (rgbKey,
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mode,
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rgbIV,
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BlockSizeValue,
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feedbackSize,
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PaddingValue,
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encryptMode);
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}
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}
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} |