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New AesCfb

pull/3006/head
Bruce Wayne 3 years ago
parent
f738fda7ca
commit
66d50af39a
No known key found for this signature in database GPG Key ID: 6D396097F05051BF
2 changed files with 13 additions and 278 deletions
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  1. +0
    -235
      Shadowsocks.Net/Crypto/Stream/ExtendedCfbBlockCipher.cs
  2. +13
    -43
      Shadowsocks.Net/Crypto/Stream/StreamAesBouncyCastleCrypto.cs

+ 0
- 235
Shadowsocks.Net/Crypto/Stream/ExtendedCfbBlockCipher.cs View File

@@ -1,235 +0,0 @@
// original: https://github.com/bcgit/bc-csharp/blob/master/crypto/src/crypto/modes/CfbBlockCipher.cs
// changes: 5th parameter for ProcessBlock, to process without change internal state


using Org.BouncyCastle.Crypto.Parameters;
using System;

namespace Org.BouncyCastle.Crypto.Modes
{
/**
* implements a Cipher-FeedBack (CFB) mode on top of a simple cipher.
*/
public class ExtendedCfbBlockCipher
: IBlockCipher
{
private readonly byte[] IV;
private readonly byte[] cfbV;
private readonly byte[] cfbOutV;
private bool encrypting;

private readonly int blockSize;
private readonly IBlockCipher cipher;

/**
* Basic constructor.
*
* @param cipher the block cipher to be used as the basis of the
* feedback mode.
* @param blockSize the block size in bits (note: a multiple of 8)
*/
public ExtendedCfbBlockCipher(
IBlockCipher cipher,
int bitBlockSize)
{
this.cipher = cipher;
blockSize = bitBlockSize / 8;
IV = new byte[cipher.GetBlockSize()];
cfbV = new byte[cipher.GetBlockSize()];
cfbOutV = new byte[cipher.GetBlockSize()];
}
/**
* return the underlying block cipher that we are wrapping.
*
* @return the underlying block cipher that we are wrapping.
*/
public IBlockCipher GetUnderlyingCipher()
{
return cipher;
}
/**
* Initialise the cipher and, possibly, the initialisation vector (IV).
* If an IV isn't passed as part of the parameter, the IV will be all zeros.
* An IV which is too short is handled in FIPS compliant fashion.
*
* @param forEncryption if true the cipher is initialised for
* encryption, if false for decryption.
* @param param the key and other data required by the cipher.
* @exception ArgumentException if the parameters argument is
* inappropriate.
*/
public void Init(
bool forEncryption,
ICipherParameters parameters)
{
encrypting = forEncryption;
if (parameters is ParametersWithIV ivParam)
{
byte[] iv = ivParam.GetIV();
int diff = IV.Length - iv.Length;
Array.Copy(iv, 0, IV, diff, iv.Length);
Array.Clear(IV, 0, diff);

parameters = ivParam.Parameters;
}
Reset();

// if it's null, key is to be reused.
if (parameters != null)
{
cipher.Init(true, parameters);
}
}

/**
* return the algorithm name and mode.
*
* @return the name of the underlying algorithm followed by "/CFB"
* and the block size in bits.
*/
public string AlgorithmName => cipher.AlgorithmName + "/CFB" + (blockSize * 8);

public bool IsPartialBlockOkay => true;

/**
* return the block size we are operating at.
*
* @return the block size we are operating at (in bytes).
*/
public int GetBlockSize()
{
return blockSize;
}

/**
* Process one block of input from the array in and write it to
* the out array.
*
* @param in the array containing the input data.
* @param inOff offset into the in array the data starts at.
* @param out the array the output data will be copied into.
* @param outOff the offset into the out array the output will start at.
* @param updateContext update internal state after process.
* @exception DataLengthException if there isn't enough data in in, or
* space in out.
* @exception InvalidOperationException if the cipher isn't initialised.
* @return the number of bytes processed and produced.
*/
public int ProcessBlock(
byte[] input,
int inOff,
byte[] output,
int outOff,
bool updateContext)
{
return (encrypting)
? EncryptBlock(input, inOff, output, outOff, updateContext)
: DecryptBlock(input, inOff, output, outOff, updateContext);
}

/**
* Do the appropriate processing for CFB mode encryption.
*
* @param in the array containing the data to be encrypted.
* @param inOff offset into the in array the data starts at.
* @param out the array the encrypted data will be copied into.
* @param outOff the offset into the out array the output will start at.
* @exception DataLengthException if there isn't enough data in in, or
* space in out.
* @exception InvalidOperationException if the cipher isn't initialised.
* @return the number of bytes processed and produced.
*/
public int EncryptBlock(
byte[] input,
int inOff,
byte[] outBytes,
int outOff,
bool updateContext = true)
{
if ((inOff + blockSize) > input.Length)
{
throw new DataLengthException("input buffer too short");
}
if ((outOff + blockSize) > outBytes.Length)
{
throw new DataLengthException("output buffer too short");
}
cipher.ProcessBlock(cfbV, 0, cfbOutV, 0);
//
// XOR the cfbV with the plaintext producing the ciphertext
//
for (int i = 0; i < blockSize; i++)
{
outBytes[outOff + i] = (byte)(cfbOutV[i] ^ input[inOff + i]);
}
if (updateContext)
{
//
// change over the input block.
//
Array.Copy(cfbV, blockSize, cfbV, 0, cfbV.Length - blockSize);
Array.Copy(outBytes, outOff, cfbV, cfbV.Length - blockSize, blockSize);
}
return blockSize;
}
/**
* Do the appropriate processing for CFB mode decryption.
*
* @param in the array containing the data to be decrypted.
* @param inOff offset into the in array the data starts at.
* @param out the array the encrypted data will be copied into.
* @param outOff the offset into the out array the output will start at.
* @exception DataLengthException if there isn't enough data in in, or
* space in out.
* @exception InvalidOperationException if the cipher isn't initialised.
* @return the number of bytes processed and produced.
*/
public int DecryptBlock(
byte[] input,
int inOff,
byte[] outBytes,
int outOff,
bool updateContext = true)
{
if ((inOff + blockSize) > input.Length)
{
throw new DataLengthException("input buffer too short");
}
if ((outOff + blockSize) > outBytes.Length)
{
throw new DataLengthException("output buffer too short");
}
cipher.ProcessBlock(cfbV, 0, cfbOutV, 0);
if (updateContext)
{
//
// change over the input block.
//
Array.Copy(cfbV, blockSize, cfbV, 0, cfbV.Length - blockSize);
Array.Copy(input, inOff, cfbV, cfbV.Length - blockSize, blockSize);
}
//
// XOR the cfbV with the ciphertext producing the plaintext
//
for (int i = 0; i < blockSize; i++)
{
outBytes[outOff + i] = (byte)(cfbOutV[i] ^ input[inOff + i]);
}
return blockSize;
}
/**
* reset the chaining vector back to the IV and reset the underlying
* cipher.
*/
public void Reset()
{
Array.Copy(IV, 0, cfbV, 0, IV.Length);
cipher.Reset();
}

public int ProcessBlock(byte[] inBuf, int inOff, byte[] outBuf, int outOff)
{
return ProcessBlock(inBuf, inOff, outBuf, outOff, true);
}
}
}

+ 13
- 43
Shadowsocks.Net/Crypto/Stream/StreamAesBouncyCastleCrypto.cs View File

@@ -1,21 +1,18 @@
using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.Crypto.Modes;
using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.Crypto.Parameters;
using Shadowsocks.Net.Crypto.Extensions;
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;

namespace Shadowsocks.Net.Crypto.Stream
{

public class StreamAesCfbBouncyCastleCrypto : StreamCrypto
{
readonly byte[] cfbBuf = new byte[MaxInputSize + 128];
int ptr = 0;
readonly ExtendedCfbBlockCipher b;
private readonly MyCfbBlockCipher b;
public StreamAesCfbBouncyCastleCrypto(string method, string password) : base(method, password)
{
b = new ExtendedCfbBlockCipher(new AesEngine(), 128);
b = new MyCfbBlockCipher(new AesEngine(), 128);
}

protected override void InitCipher(byte[] iv, bool isEncrypt)
@@ -26,49 +23,22 @@ namespace Shadowsocks.Net.Crypto.Stream

protected override int CipherEncrypt(ReadOnlySpan<byte> plain, Span<byte> cipher)
{
CipherUpdate(plain, cipher);
return plain.Length;
return CipherUpdate(plain, cipher);
}

protected override int CipherDecrypt(Span<byte> plain, ReadOnlySpan<byte> cipher)
{
CipherUpdate(cipher, plain);
return cipher.Length;
return CipherUpdate(cipher, plain);
}

[MethodImpl( MethodImplOptions.AggressiveInlining)]
private void CipherUpdate(ReadOnlySpan<byte> i, Span<byte> o)
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private int CipherUpdate(ReadOnlySpan<byte> input, Span<byte> output)
{
Span<byte> ob = new byte[o.Length + 128];
i.CopyTo(cfbBuf.AsSpan(ptr));
// TODO: standard CFB, maybe with native aes
int total = i.Length + ptr;

int blkSize = b.GetBlockSize();

int blkCount = total / blkSize;
int restSize = total % blkSize;
int readPtr = 0;

byte[] tmp = new byte[blkSize];
for (int j = 0; j < blkCount; j++)
{
b.ProcessBlock(cfbBuf, readPtr, tmp, 0);
tmp.CopyTo(ob.Slice(readPtr));
readPtr += blkSize;
}
if (restSize != 0)
{
readPtr = blkSize * blkCount;
// process last (partial) block without update state
b.ProcessBlock(cfbBuf, readPtr, tmp, 0, false);
tmp.CopyTo(ob.Slice(readPtr));
// write back the partial block block
Array.Copy(cfbBuf, readPtr, cfbBuf, 0, restSize);
}
// cut correct part to output
ob.Slice(ptr, o.Length).CopyTo(o);
ptr = restSize;
var i = input.ToArray();
var o = new byte[i.Length];
var res = b.ProcessBlock(i, 0, o, 0);
o.CopyTo(output);
return res;
}

#region Cipher Info


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