public override int Transform(byte[] input, int inputOffset, int count, byte[] output, int outputOffset)
{
Debug.Assert(input != null);
Debug.Assert(inputOffset >= 0);
Debug.Assert(count > 0);
Debug.Assert((count % BlockSizeInBytes) == 0);
Debug.Assert(input.Length - inputOffset >= count);
Debug.Assert(output != null);
Debug.Assert(outputOffset >= 0);
Debug.Assert(output.Length - outputOffset >= count);
int numBytesWritten;
if (_encrypting)
{
numBytesWritten = _hKey.BCryptEncrypt(input, inputOffset, count, _currentIv, output, outputOffset, output.Length - outputOffset);
}
else
{
numBytesWritten = _hKey.BCryptDecrypt(input, inputOffset, count, _currentIv, output, outputOffset, output.Length - outputOffset);
}
if (numBytesWritten != count)
{
// CNG gives us no way to tell BCryptDecrypt() that we're decrypting the final block, nor is it performing any
// padding /depadding for us. So there's no excuse for a provider to hold back output for "future calls." Though
// this isn't technically our problem to detect, we might as well detect it now for easier diagnosis.
throw new CryptographicException(SR.Cryptography_UnexpectedTransformTruncation);
}
return(numBytesWritten);
}
protected sealed override byte[] UncheckedTransformFinalBlock(SafeKeyHandle hKey, byte[] currentIv, byte[] inputBuffer, int inputOffset, int inputCount)
{
byte[] paddedBlock = PadBlock(inputBuffer, inputOffset, inputCount);
byte[] output = new byte[paddedBlock.Length];
hKey.BCryptEncrypt(paddedBlock, 0, paddedBlock.Length, currentIv, output, 0, output.Length);
return output;
}
protected sealed override byte[] UncheckedTransformFinalBlock(SafeKeyHandle hKey, byte[] currentIv, byte[] inputBuffer, int inputOffset, int inputCount)
{
byte[] paddedBlock = PadBlock(inputBuffer, inputOffset, inputCount);
byte[] output = new byte[paddedBlock.Length];
hKey.BCryptEncrypt(paddedBlock, 0, paddedBlock.Length, currentIv, output, 0, output.Length);
return(output);
}
protected sealed override int UncheckedTransformBlock(SafeKeyHandle hKey, byte[] currentIv, byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
{
int numBytesWritten = hKey.BCryptEncrypt(inputBuffer, inputOffset, inputCount, currentIv, outputBuffer, outputOffset, outputBuffer.Length);
return numBytesWritten;
}
protected sealed override int UncheckedTransformBlock(SafeKeyHandle hKey, byte[] currentIv, byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
{
int numBytesWritten = hKey.BCryptEncrypt(inputBuffer, inputOffset, inputCount, currentIv, outputBuffer, outputOffset, outputBuffer.Length);
return(numBytesWritten);
}