#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
using System;
using Org.BouncyCastle.Crypto.Modes;
using Org.BouncyCastle.Crypto.Paddings;
using Org.BouncyCastle.Crypto.Parameters;
namespace Org.BouncyCastle.Crypto.Macs
{
/**
* implements a Cipher-FeedBack (CFB) mode on top of a simple cipher.
*/
class MacCFBBlockCipher
: IBlockCipher
{
private byte[] IV;
private byte[] cfbV;
private byte[] cfbOutV;
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 MacCFBBlockCipher(
IBlockCipher cipher,
int bitBlockSize)
{
this.cipher = cipher;
this.blockSize = bitBlockSize / 8;
this.IV = new byte[cipher.GetBlockSize()];
this.cfbV = new byte[cipher.GetBlockSize()];
this.cfbOutV = new byte[cipher.GetBlockSize()];
}
/**
* 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 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)
{
if (parameters is ParametersWithIV)
{
ParametersWithIV ivParam = (ParametersWithIV)parameters;
byte[] iv = ivParam.GetIV();
if (iv.Length < IV.Length)
{
Array.Copy(iv, 0, IV, IV.Length - iv.Length, iv.Length);
}
else
{
Array.Copy(iv, 0, IV, 0, IV.Length);
}
parameters = ivParam.Parameters;
}
Reset();
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
{
get { return cipher.AlgorithmName + "/CFB" + (blockSize * 8); }
}
public bool IsPartialBlockOkay
{
get { return 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.
* @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[] outBytes,
int outOff)
{
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 cipher text
//
for (int i = 0; i < blockSize; i++)
{
outBytes[outOff + i] = (byte)(cfbOutV[i] ^ input[inOff + i]);
}
//
// 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;
}
/**
* reset the chaining vector back to the IV and reset the underlying
* cipher.
*/
public void Reset()
{
IV.CopyTo(cfbV, 0);
cipher.Reset();
}
public void GetMacBlock(
byte[] mac)
{
cipher.ProcessBlock(cfbV, 0, mac, 0);
}
}
public class CfbBlockCipherMac
: IMac
{
private byte[] mac;
private byte[] Buffer;
private int bufOff;
private MacCFBBlockCipher cipher;
private IBlockCipherPadding padding;
private int macSize;
/**
* create a standard MAC based on a CFB block cipher. This will produce an
* authentication code half the length of the block size of the cipher, with
* the CFB mode set to 8 bits.
*
* @param cipher the cipher to be used as the basis of the MAC generation.
*/
public CfbBlockCipherMac(
IBlockCipher cipher)
: this(cipher, 8, (cipher.GetBlockSize() * 8) / 2, null)
{
}
/**
* create a standard MAC based on a CFB block cipher. This will produce an
* authentication code half the length of the block size of the cipher, with
* the CFB mode set to 8 bits.
*
* @param cipher the cipher to be used as the basis of the MAC generation.
* @param padding the padding to be used.
*/
public CfbBlockCipherMac(
IBlockCipher cipher,
IBlockCipherPadding padding)
: this(cipher, 8, (cipher.GetBlockSize() * 8) / 2, padding)
{
}
/**
* create a standard MAC based on a block cipher with the size of the
* MAC been given in bits. This class uses CFB mode as the basis for the
* MAC generation.
* <p>
* Note: the size of the MAC must be at least 24 bits (FIPS Publication 81),
* or 16 bits if being used as a data authenticator (FIPS Publication 113),
* and in general should be less than the size of the block cipher as it reduces
* the chance of an exhaustive attack (see Handbook of Applied Cryptography).
* </p>
* @param cipher the cipher to be used as the basis of the MAC generation.
* @param cfbBitSize the size of an output block produced by the CFB mode.
* @param macSizeInBits the size of the MAC in bits, must be a multiple of 8.
*/
public CfbBlockCipherMac(
IBlockCipher cipher,
int cfbBitSize,
int macSizeInBits)
: this(cipher, cfbBitSize, macSizeInBits, null)
{
}
/**
* create a standard MAC based on a block cipher with the size of the
* MAC been given in bits. This class uses CFB mode as the basis for the
* MAC generation.
* <p>
* Note: the size of the MAC must be at least 24 bits (FIPS Publication 81),
* or 16 bits if being used as a data authenticator (FIPS Publication 113),
* and in general should be less than the size of the block cipher as it reduces
* the chance of an exhaustive attack (see Handbook of Applied Cryptography).
* </p>
* @param cipher the cipher to be used as the basis of the MAC generation.
* @param cfbBitSize the size of an output block produced by the CFB mode.
* @param macSizeInBits the size of the MAC in bits, must be a multiple of 8.
* @param padding a padding to be used.
*/
public CfbBlockCipherMac(
IBlockCipher cipher,
int cfbBitSize,
int macSizeInBits,
IBlockCipherPadding padding)
{
if ((macSizeInBits % 8) != 0)
throw new ArgumentException("MAC size must be multiple of 8");
mac = new byte[cipher.GetBlockSize()];
this.cipher = new MacCFBBlockCipher(cipher, cfbBitSize);
this.padding = padding;
this.macSize = macSizeInBits / 8;
Buffer = new byte[this.cipher.GetBlockSize()];
bufOff = 0;
}
public string AlgorithmName
{
get { return cipher.AlgorithmName; }
}
public void Init(
ICipherParameters parameters)
{
Reset();
cipher.Init(true, parameters);
}
public int GetMacSize()
{
return macSize;
}
public void Update(
byte input)
{
if (bufOff == Buffer.Length)
{
cipher.ProcessBlock(Buffer, 0, mac, 0);
bufOff = 0;
}
Buffer[bufOff++] = input;
}
public void BlockUpdate(
byte[] input,
int inOff,
int len)
{
if (len < 0)
throw new ArgumentException("Can't have a negative input length!");
int blockSize = cipher.GetBlockSize();
int resultLen = 0;
int gapLen = blockSize - bufOff;
if (len > gapLen)
{
Array.Copy(input, inOff, Buffer, bufOff, gapLen);
resultLen += cipher.ProcessBlock(Buffer, 0, mac, 0);
bufOff = 0;
len -= gapLen;
inOff += gapLen;
while (len > blockSize)
{
resultLen += cipher.ProcessBlock(input, inOff, mac, 0);
len -= blockSize;
inOff += blockSize;
}
}
Array.Copy(input, inOff, Buffer, bufOff, len);
bufOff += len;
}
public int DoFinal(
byte[] output,
int outOff)
{
int blockSize = cipher.GetBlockSize();
// pad with zeroes
if (this.padding == null)
{
while (bufOff < blockSize)
{
Buffer[bufOff++] = 0;
}
}
else
{
padding.AddPadding(Buffer, bufOff);
}
cipher.ProcessBlock(Buffer, 0, mac, 0);
cipher.GetMacBlock(mac);
Array.Copy(mac, 0, output, outOff, macSize);
Reset();
return macSize;
}
/**
* Reset the mac generator.
*/
public void Reset()
{
// Clear the buffer.
Array.Clear(Buffer, 0, Buffer.Length);
bufOff = 0;
// Reset the underlying cipher.
cipher.Reset();
}
}
}
#endif