128 lines
3.7 KiB
C#
128 lines
3.7 KiB
C#
/*
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Twofish Cipher for KeePass Password Safe
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Copyright (C) 2009-2010 SEG Tech <me@gogogadgetscott.info>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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using System;
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using System.Collections.Generic;
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using System.Text;
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using System.IO;
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using System.Security;
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using System.Security.Cryptography;
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using System.Diagnostics;
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using KeePassLib;
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using KeePassLib.Cryptography.Cipher;
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using TwofishCipher.Crypto;
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namespace TwofishCipher
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{
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public sealed class TwofishCipherEngine : ICipherEngine
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{
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private const CipherMode m_rCipherMode = CipherMode.CBC;
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private const PaddingMode m_rCipherPadding = PaddingMode.PKCS7;
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private PwUuid m_uuidCipher;
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public static readonly byte[] TwofishCipherUuidBytes = new byte[]{
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0xAD, 0x68, 0xF2, 0x9F, 0x57, 0x6F, 0x4B, 0xB9,
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0xA3, 0x6A, 0xD4, 0x7A, 0xF9, 0x65, 0x34, 0x6C
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};
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public TwofishCipherEngine()
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{
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m_uuidCipher = new PwUuid(TwofishCipherUuidBytes);
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}
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public PwUuid CipherUuid
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{
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get
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{
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Debug.Assert(m_uuidCipher != null);
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return m_uuidCipher;
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}
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}
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public string DisplayName
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{
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get { return "Twofish (256-Bit Key)"; }
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}
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private static void ValidateArguments(Stream stream, bool bEncrypt, byte[] pbKey, byte[] pbIV)
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{
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Debug.Assert(stream != null); if(stream == null) throw new ArgumentNullException("stream");
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Debug.Assert(pbKey != null); if(pbKey == null) throw new ArgumentNullException("pbKey");
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Debug.Assert(pbKey.Length == 32);
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if(pbKey.Length != 32) throw new ArgumentException("Key must be 256 bits wide!");
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Debug.Assert(pbIV != null); if(pbIV == null) throw new ArgumentNullException("pbIV");
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Debug.Assert(pbIV.Length == 16);
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if(pbIV.Length != 16) throw new ArgumentException("Initialization vector must be 128 bits wide!");
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if(bEncrypt)
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{
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Debug.Assert(stream.CanWrite);
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if(stream.CanWrite == false) throw new ArgumentException("Stream must be writable!");
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}
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else // Decrypt
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{
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Debug.Assert(stream.CanRead);
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if(stream.CanRead == false) throw new ArgumentException("Encrypted stream must be readable!");
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}
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}
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private static Stream CreateStream(Stream s, bool bEncrypt, byte[] pbKey, byte[] pbIV)
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{
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ValidateArguments(s, bEncrypt, pbKey, pbIV);
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Twofish f = new Twofish();
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byte[] pbLocalIV = new byte[16];
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Array.Copy(pbIV, pbLocalIV, 16);
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f.IV = pbLocalIV;
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byte[] pbLocalKey = new byte[32];
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Array.Copy(pbKey, pbLocalKey, 32);
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f.KeySize = 256;
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f.Key = pbLocalKey;
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f.Mode = m_rCipherMode;
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f.Padding = m_rCipherPadding;
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ICryptoTransform iTransform = (bEncrypt ? f.CreateEncryptor() : f.CreateDecryptor());
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Debug.Assert(iTransform != null);
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if(iTransform == null) throw new SecurityException("Unable to create Twofish transform!");
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return new CryptoStream(s, iTransform, bEncrypt ? CryptoStreamMode.Write :
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CryptoStreamMode.Read);
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}
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public Stream EncryptStream(Stream sPlainText, byte[] pbKey, byte[] pbIV)
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{
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return CreateStream(sPlainText, true, pbKey, pbIV);
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}
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public Stream DecryptStream(Stream sEncrypted, byte[] pbKey, byte[] pbIV)
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{
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return CreateStream(sEncrypted, false, pbKey, pbIV);
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}
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}
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}
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