public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount)
{
if (inputBuffer == null)
{
throw new ArgumentNullException("inputBuffer");
}
if (inputOffset < 0)
{
throw new ArgumentOutOfRangeException("inputOffset");
}
if (inputCount < 0)
{
throw new ArgumentOutOfRangeException("inputCount");
}
if (inputCount > inputBuffer.Length - inputOffset)
{
throw new ArgumentOutOfRangeException("inputCount");
}
if (m_encrypting)
{
// We need to pad the final block before encrypting it
byte[] paddedBlock = m_paddingMode.PadBlock(inputBuffer, inputOffset, inputCount);
if (paddedBlock.Length > 0)
{
return(BCryptNative.SymmetricEncrypt(m_key, m_iv, paddedBlock));
}
else
{
return(paddedBlock);
}
}
else
{
// We can't decrypt a partial final block
if (inputCount % InputBlockSize != 0)
{
throw new CryptographicException(Properties.Resources.CannotDecryptPartialBlock);
}
// Decrypt all remaining data
byte[] plaintext = new byte[inputCount + (m_depadBuffer != null ? m_depadBuffer.Length : 0)];
int plaintextLength = DecryptBlocks(inputBuffer, inputOffset, inputCount, plaintext, 0, false);
// Remove any padding
return(m_paddingMode.DepadBlock(plaintext, 0, plaintextLength));
}
}
private int EncryptBlocks(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
{
Debug.Assert(inputBuffer != null, "inputBuffer != null");
Debug.Assert(inputOffset >= 0, "inputOffset >= 0");
Debug.Assert(inputCount >= 0 && inputCount <= inputBuffer.Length - inputOffset, "inputCount >= 0 && inputCount <= inputBuffer.Length - inputOffset");
Debug.Assert(inputCount % InputBlockSize == 0, "inputCount % InputBlockSize == 0");
Debug.Assert(outputBuffer != null, "outputBuffer != null");
Debug.Assert(inputCount <= outputBuffer.Length - outputOffset, "inputCount <= outputBuffer.Length - outputOffset");
// Pull the input into a stand alone array
byte[] plaintext = new byte[inputCount];
Buffer.BlockCopy(inputBuffer, inputOffset, plaintext, 0, plaintext.Length);
// Do the encryption
byte[] ciphertext = BCryptNative.SymmetricEncrypt(m_key, m_iv, plaintext);
// Copy the output to the destination array
Buffer.BlockCopy(ciphertext, 0, outputBuffer, outputOffset, ciphertext.Length);
return(ciphertext.Length);
}
private byte[] CngTransform(byte[] input, int inputOffset, int inputCount)
{
Debug.Assert(m_key != null, "key != null");
Debug.Assert(!m_key.IsClosed && !m_key.IsInvalid, "!m_key.IsClosed && !m_key.IsInvalid");
Debug.Assert(input != null, "input != null");
Debug.Assert(inputOffset >= 0, "inputOffset >= 0");
Debug.Assert(inputCount >= 0, "inputCount >= 0");
Debug.Assert(inputCount <= input.Length - inputOffset, "inputCount <= input.Length - inputOffset");
byte[] inputBuffer = null;
try
{
// Build up a buffer of the only portion of the input we should be transforming
inputBuffer = input;
if (inputOffset > 0 || inputCount != input.Length)
{
inputBuffer = new byte[inputCount];
Array.Copy(input, inputOffset, inputBuffer, 0, inputBuffer.Length);
}
if (m_encrypting)
{
return(BCryptNative.SymmetricEncrypt(m_key, inputBuffer, m_chainData, ref m_authInfo));
}
else
{
return(BCryptNative.SymmetricDecrypt(m_key, inputBuffer, this.m_chainData, ref m_authInfo));
}
}
finally
{
if (inputBuffer != input)
{
// Zeroize the input buffer if we allocated one
Array.Clear(inputBuffer, 0, inputBuffer.Length);
}
}
}
