CbcCipherMode
Implements CBC cipher mode.
using System;
using System.Globalization;
namespace Renci.SshNet.Security.Cryptography.Ciphers.Modes
{
public class CbcCipherMode : CipherMode
{
public CbcCipherMode(byte[] iv)
: base(iv)
{
}
public override int EncryptBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
{
if (inputBuffer.Length - inputOffset < _blockSize)
throw new ArgumentException("Invalid input buffer");
if (outputBuffer.Length - outputOffset < _blockSize)
throw new ArgumentException("Invalid output buffer");
if (inputCount != _blockSize)
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, "inputCount must be {0}.", _blockSize));
for (int i = 0; i < _blockSize; i++) {
IV[i] ^= inputBuffer[inputOffset + i];
}
Cipher.EncryptBlock(IV, 0, inputCount, outputBuffer, outputOffset);
Buffer.BlockCopy(outputBuffer, outputOffset, IV, 0, IV.Length);
return _blockSize;
}
public override int DecryptBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
{
if (inputBuffer.Length - inputOffset < _blockSize)
throw new ArgumentException("Invalid input buffer");
if (outputBuffer.Length - outputOffset < _blockSize)
throw new ArgumentException("Invalid output buffer");
if (inputCount != _blockSize)
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, "inputCount must be {0}.", _blockSize));
Cipher.DecryptBlock(inputBuffer, inputOffset, inputCount, outputBuffer, outputOffset);
for (int i = 0; i < _blockSize; i++) {
outputBuffer[outputOffset + i] ^= IV[i];
}
Buffer.BlockCopy(inputBuffer, inputOffset, IV, 0, IV.Length);
return _blockSize;
}
}
}