public byte[] TransformFinalBlock(byte[] input, int inputOffset, int count)
{
ulong ivLength = this.iv == null ? 0 : (ulong)this.iv.Length;
uint result;
ulong outputSize;
// Get the required size of the plaintext/ciphertext buffer
if (this.isEncrypting)
{
result = BCryptCore.BCryptEncrypt(this.hKey, input, (ulong)count, IntPtr.Zero, this.iv, ivLength, null, 0, out outputSize, BCryptConstants.BCRYPT_BLOCK_PADDING);
if (result != 0)
{
throw new SystemException("An error was encountered while retrieving the ciphertext size.");
}
}
else
{
result = BCryptCore.BCryptDecrypt(this.hKey, input, (ulong)count, IntPtr.Zero, this.iv, ivLength, null, 0, out outputSize, BCryptConstants.BCRYPT_BLOCK_PADDING);
if (result != 0)
{
throw new SystemException("An error was encountered while retrieving the plaintext size.");
}
}
byte[] output = new byte[outputSize];
// No padding is used with authenticatied modes
// Bypass final block transformation and defer to regular transformation
if (this.mode == BlockCipherMode.GCM || this.mode == BlockCipherMode.CCM)
{
this.TransformBlock(input, inputOffset, output, 0, count);
return(output);
}
ulong pcbResult;
if (this.isEncrypting)
{
result = BCryptCore.BCryptEncrypt(this.hKey, input, (ulong)count, IntPtr.Zero, this.iv, ivLength, output, (ulong)output.Length, out pcbResult, BCryptConstants.BCRYPT_BLOCK_PADDING);
if (result != 0)
{
throw new SystemException("An error was encountered during encryption.");
}
}
else
{
result = BCryptCore.BCryptDecrypt(this.hKey, input, (ulong)count, IntPtr.Zero, this.iv, ivLength, output, (ulong)output.Length, out pcbResult, BCryptConstants.BCRYPT_BLOCK_PADDING);
if (result != 0)
{
throw new SystemException("An error was encountered during decryption.");
}
}
return(output);
}
public void TransformBlock(byte[] input, int inputOffset, byte[] output, int outputOffset, int count)
{
ulong pcbResult;
ulong ivLength = this.iv == null ? 0 : (ulong)this.iv.Length;
if (this.isEncrypting)
{
uint result = BCryptCore.BCryptEncrypt(this.hKey, input, (ulong)count, IntPtr.Zero, this.iv, ivLength, output, (ulong)output.Length, out pcbResult, BCryptConstants.BCRYPT_NO_PADDING);
if (result != 0)
{
throw new SystemException("An error was encountered during encryption.");
}
}
else
{
uint result = BCryptCore.BCryptDecrypt(this.hKey, input, (ulong)count, IntPtr.Zero, this.iv, ivLength, output, (ulong)output.Length, out pcbResult, BCryptConstants.BCRYPT_NO_PADDING);
if (result != 0)
{
throw new SystemException("An error was encountered during decryption.");
}
}
}