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Geoffroy BONNEVILLE
2019-07-25 16:39:43 +02:00
parent 81509be167
commit 1b2007e6dd
136 changed files with 35834 additions and 0 deletions
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ModernKeePassLib/Cryptography/Cipher/ChaCha20Cipher.cs Normal file
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/*
KeePass Password Safe - The Open-Source Password Manager
Copyright (C) 2003-2019 Dominik Reichl <dominik.reichl@t-online.de>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using ModernKeePassLib.Resources;
using ModernKeePassLib.Utility;
namespace ModernKeePassLib.Cryptography.Cipher
{
/// <summary>
/// Implementation of the ChaCha20 cipher with a 96-bit nonce,
/// as specified in RFC 7539.
/// https://tools.ietf.org/html/rfc7539
/// </summary>
public sealed class ChaCha20Cipher : CtrBlockCipher
{
private uint[] m_s = new uint[16]; // State
private uint[] m_x = new uint[16]; // Working buffer
private bool m_bLargeCounter; // See constructor documentation
private static readonly uint[] g_sigma = new uint[4] {
0x61707865, 0x3320646E, 0x79622D32, 0x6B206574
};
private const string StrNameRfc = "ChaCha20 (RFC 7539)";
public override int BlockSize
{
get { return 64; }
}
public ChaCha20Cipher(byte[] pbKey32, byte[] pbIV12) :
this(pbKey32, pbIV12, false)
{
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="pbKey32">Key (32 bytes).</param>
/// <param name="pbIV12">Nonce (12 bytes).</param>
/// <param name="bLargeCounter">If <c>false</c>, the RFC 7539 version
/// of ChaCha20 is used. In this case, only 256 GB of data can be
/// encrypted securely (because the block counter is a 32-bit variable);
/// an attempt to encrypt more data throws an exception.
/// If <paramref name="bLargeCounter" /> is <c>true</c>, the 32-bit
/// counter overflows to another 32-bit variable (i.e. the counter
/// effectively is a 64-bit variable), like in the original ChaCha20
/// specification by D. J. Bernstein (which has a 64-bit counter and a
/// 64-bit nonce). To be compatible with this version, the 64-bit nonce
/// must be stored in the last 8 bytes of <paramref name="pbIV12" />
/// and the first 4 bytes must be 0.
/// If the IV was generated randomly, a 12-byte IV and a large counter
/// can be used to securely encrypt more than 256 GB of data (but note
/// this is incompatible with RFC 7539 and the original specification).</param>
public ChaCha20Cipher(byte[] pbKey32, byte[] pbIV12, bool bLargeCounter) :
base()
{
if(pbKey32 == null) throw new ArgumentNullException("pbKey32");
if(pbKey32.Length != 32) throw new ArgumentOutOfRangeException("pbKey32");
if(pbIV12 == null) throw new ArgumentNullException("pbIV12");
if(pbIV12.Length != 12) throw new ArgumentOutOfRangeException("pbIV12");
m_bLargeCounter = bLargeCounter;
// Key setup
m_s[4] = MemUtil.BytesToUInt32(pbKey32, 0);
m_s[5] = MemUtil.BytesToUInt32(pbKey32, 4);
m_s[6] = MemUtil.BytesToUInt32(pbKey32, 8);
m_s[7] = MemUtil.BytesToUInt32(pbKey32, 12);
m_s[8] = MemUtil.BytesToUInt32(pbKey32, 16);
m_s[9] = MemUtil.BytesToUInt32(pbKey32, 20);
m_s[10] = MemUtil.BytesToUInt32(pbKey32, 24);
m_s[11] = MemUtil.BytesToUInt32(pbKey32, 28);
m_s[0] = g_sigma[0];
m_s[1] = g_sigma[1];
m_s[2] = g_sigma[2];
m_s[3] = g_sigma[3];
// IV setup
m_s[12] = 0; // Counter
m_s[13] = MemUtil.BytesToUInt32(pbIV12, 0);
m_s[14] = MemUtil.BytesToUInt32(pbIV12, 4);
m_s[15] = MemUtil.BytesToUInt32(pbIV12, 8);
}
protected override void Dispose(bool bDisposing)
{
if(bDisposing)
{
MemUtil.ZeroArray<uint>(m_s);
MemUtil.ZeroArray<uint>(m_x);
}
base.Dispose(bDisposing);
}
protected override void NextBlock(byte[] pBlock)
{
if(pBlock == null) throw new ArgumentNullException("pBlock");
if(pBlock.Length != 64) throw new ArgumentOutOfRangeException("pBlock");
// x is a local alias for the working buffer; with this,
// the compiler/runtime might remove some checks
uint[] x = m_x;
if(x == null) throw new InvalidOperationException();
if(x.Length < 16) throw new InvalidOperationException();
uint[] s = m_s;
if(s == null) throw new InvalidOperationException();
if(s.Length < 16) throw new InvalidOperationException();
Array.Copy(s, x, 16);
unchecked
{
// 10 * 8 quarter rounds = 20 rounds
for(int i = 0; i < 10; ++i)
{
// Column quarter rounds
x[ 0] += x[ 4];
x[12] = MemUtil.RotateLeft32(x[12] ^ x[ 0], 16);
x[ 8] += x[12];
x[ 4] = MemUtil.RotateLeft32(x[ 4] ^ x[ 8], 12);
x[ 0] += x[ 4];
x[12] = MemUtil.RotateLeft32(x[12] ^ x[ 0], 8);
x[ 8] += x[12];
x[ 4] = MemUtil.RotateLeft32(x[ 4] ^ x[ 8], 7);
x[ 1] += x[ 5];
x[13] = MemUtil.RotateLeft32(x[13] ^ x[ 1], 16);
x[ 9] += x[13];
x[ 5] = MemUtil.RotateLeft32(x[ 5] ^ x[ 9], 12);
x[ 1] += x[ 5];
x[13] = MemUtil.RotateLeft32(x[13] ^ x[ 1], 8);
x[ 9] += x[13];
x[ 5] = MemUtil.RotateLeft32(x[ 5] ^ x[ 9], 7);
x[ 2] += x[ 6];
x[14] = MemUtil.RotateLeft32(x[14] ^ x[ 2], 16);
x[10] += x[14];
x[ 6] = MemUtil.RotateLeft32(x[ 6] ^ x[10], 12);
x[ 2] += x[ 6];
x[14] = MemUtil.RotateLeft32(x[14] ^ x[ 2], 8);
x[10] += x[14];
x[ 6] = MemUtil.RotateLeft32(x[ 6] ^ x[10], 7);
x[ 3] += x[ 7];
x[15] = MemUtil.RotateLeft32(x[15] ^ x[ 3], 16);
x[11] += x[15];
x[ 7] = MemUtil.RotateLeft32(x[ 7] ^ x[11], 12);
x[ 3] += x[ 7];
x[15] = MemUtil.RotateLeft32(x[15] ^ x[ 3], 8);
x[11] += x[15];
x[ 7] = MemUtil.RotateLeft32(x[ 7] ^ x[11], 7);
// Diagonal quarter rounds
x[ 0] += x[ 5];
x[15] = MemUtil.RotateLeft32(x[15] ^ x[ 0], 16);
x[10] += x[15];
x[ 5] = MemUtil.RotateLeft32(x[ 5] ^ x[10], 12);
x[ 0] += x[ 5];
x[15] = MemUtil.RotateLeft32(x[15] ^ x[ 0], 8);
x[10] += x[15];
x[ 5] = MemUtil.RotateLeft32(x[ 5] ^ x[10], 7);
x[ 1] += x[ 6];
x[12] = MemUtil.RotateLeft32(x[12] ^ x[ 1], 16);
x[11] += x[12];
x[ 6] = MemUtil.RotateLeft32(x[ 6] ^ x[11], 12);
x[ 1] += x[ 6];
x[12] = MemUtil.RotateLeft32(x[12] ^ x[ 1], 8);
x[11] += x[12];
x[ 6] = MemUtil.RotateLeft32(x[ 6] ^ x[11], 7);
x[ 2] += x[ 7];
x[13] = MemUtil.RotateLeft32(x[13] ^ x[ 2], 16);
x[ 8] += x[13];
x[ 7] = MemUtil.RotateLeft32(x[ 7] ^ x[ 8], 12);
x[ 2] += x[ 7];
x[13] = MemUtil.RotateLeft32(x[13] ^ x[ 2], 8);
x[ 8] += x[13];
x[ 7] = MemUtil.RotateLeft32(x[ 7] ^ x[ 8], 7);
x[ 3] += x[ 4];
x[14] = MemUtil.RotateLeft32(x[14] ^ x[ 3], 16);
x[ 9] += x[14];
x[ 4] = MemUtil.RotateLeft32(x[ 4] ^ x[ 9], 12);
x[ 3] += x[ 4];
x[14] = MemUtil.RotateLeft32(x[14] ^ x[ 3], 8);
x[ 9] += x[14];
x[ 4] = MemUtil.RotateLeft32(x[ 4] ^ x[ 9], 7);
}
for(int i = 0; i < 16; ++i) x[i] += s[i];
for(int i = 0; i < 16; ++i)
{
int i4 = i << 2;
uint xi = x[i];
pBlock[i4] = (byte)xi;
pBlock[i4 + 1] = (byte)(xi >> 8);
pBlock[i4 + 2] = (byte)(xi >> 16);
pBlock[i4 + 3] = (byte)(xi >> 24);
}
++s[12];
if(s[12] == 0)
{
if(!m_bLargeCounter)
throw new InvalidOperationException(
KLRes.EncDataTooLarge.Replace(@"{PARAM}", StrNameRfc));
++s[13]; // Increment high half of large counter
}
}
}
public long Seek(long lOffset, SeekOrigin so)
{
if(so != SeekOrigin.Begin) throw new NotSupportedException();
if((lOffset < 0) || ((lOffset & 63) != 0) ||
((lOffset >> 6) > (long)uint.MaxValue))
throw new ArgumentOutOfRangeException("lOffset");
m_s[12] = (uint)(lOffset >> 6);
InvalidateBlock();
return lOffset;
}
}
}