175 lines
4.0 KiB
C#
175 lines
4.0 KiB
C#
/*
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KeePass Password Safe - The Open-Source Password Manager
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Copyright (C) 2003-2016 Dominik Reichl <dominik.reichl@t-online.de>
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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.Diagnostics;
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using System.IO;
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using System.Text;
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using KeePassLib.Resources;
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namespace KeePassLib.Cryptography.Cipher
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{
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public sealed class ChaCha20Engine : ICipherEngine2
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{
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private PwUuid m_uuid = new PwUuid(new byte[] {
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0xD6, 0x03, 0x8A, 0x2B, 0x8B, 0x6F, 0x4C, 0xB5,
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0xA5, 0x24, 0x33, 0x9A, 0x31, 0xDB, 0xB5, 0x9A
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});
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public PwUuid CipherUuid
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{
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get { return m_uuid; }
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}
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public string DisplayName
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{
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get
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{
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return ("ChaCha20 (" + KLRes.KeyBits.Replace(@"{PARAM}",
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"256") + ", RFC 7539)");
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}
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}
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public int KeyLength
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{
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get { return 32; }
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}
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public int IVLength
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{
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get { return 12; } // 96 bits
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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 new ChaCha20Stream(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 new ChaCha20Stream(sEncrypted, false, pbKey, pbIV);
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}
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}
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internal sealed class ChaCha20Stream : Stream
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{
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private Stream m_sBase;
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private readonly bool m_bWriting;
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private ChaCha20Cipher m_c;
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private byte[] m_pbBuffer = null;
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public override bool CanRead
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{
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get { return !m_bWriting; }
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}
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public override bool CanSeek
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{
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get { return false; }
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}
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public override bool CanWrite
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{
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get { return m_bWriting; }
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}
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public override long Length
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{
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get { Debug.Assert(false); throw new NotSupportedException(); }
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}
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public override long Position
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{
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get { Debug.Assert(false); throw new NotSupportedException(); }
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set { Debug.Assert(false); throw new NotSupportedException(); }
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}
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public ChaCha20Stream(Stream sBase, bool bWriting, byte[] pbKey32,
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byte[] pbIV12)
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{
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if(sBase == null) throw new ArgumentNullException("sBase");
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m_sBase = sBase;
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m_bWriting = bWriting;
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m_c = new ChaCha20Cipher(pbKey32, pbIV12);
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}
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protected override void Dispose(bool bDisposing)
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{
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if(!bDisposing) return;
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if(m_sBase != null)
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{
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m_c.Dispose();
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m_c = null;
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m_sBase.Close();
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m_sBase = null;
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}
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m_pbBuffer = null;
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}
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public override void Flush()
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{
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Debug.Assert(m_sBase != null);
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if(m_bWriting && (m_sBase != null)) m_sBase.Flush();
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}
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public override long Seek(long lOffset, SeekOrigin soOrigin)
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{
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Debug.Assert(false);
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throw new NotImplementedException();
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}
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public override void SetLength(long lValue)
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{
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Debug.Assert(false);
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throw new NotImplementedException();
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}
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public override int Read(byte[] pbBuffer, int iOffset, int nCount)
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{
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if(m_bWriting) throw new InvalidOperationException();
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int cbRead = m_sBase.Read(pbBuffer, iOffset, nCount);
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m_c.Decrypt(pbBuffer, iOffset, cbRead);
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return cbRead;
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}
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public override void Write(byte[] pbBuffer, int iOffset, int nCount)
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{
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if(nCount < 0) throw new ArgumentOutOfRangeException("nCount");
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if(nCount == 0) return;
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if(!m_bWriting) throw new InvalidOperationException();
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if((m_pbBuffer == null) || (m_pbBuffer.Length < nCount))
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m_pbBuffer = new byte[nCount];
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Array.Copy(pbBuffer, iOffset, m_pbBuffer, 0, nCount);
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m_c.Encrypt(m_pbBuffer, 0, nCount);
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m_sBase.Write(m_pbBuffer, 0, nCount);
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}
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}
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}
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