public int Transform(Buffer buffer, int length)
{
Log.Trace("BlockCipher.Transform: input length {0}", length);
using (var encryptor = encryptionAlgorithm.CreateEncryptor(encryptionKey, encryptionIV))
using (var ms = new MemoryStream(length + BlockSizeInBytes))
using (var cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
#if UNITY_WORKAROUND
// Workaround for ancient mono 2.0 of Unity3D
// Multiple Write() calls are not properly handled there.
byte[] plaintext = buffer.ToArray();
if (Log.Level <= LogLevel.Trace)
{
Log.Trace("BlockCipher.Transform: input {0}",
BitConverter.ToString(plaintext, plaintext.Length - length, length));
}
cs.Write(plaintext, plaintext.Length - length, length);
#else
var buffers = new List<ArraySegment<byte>>();
buffer.ListEndingSegments(buffers, length);
for (var i = 0; i < buffers.Count; ++i)
{
var segment = buffers[i];
if (Log.Level <= LogLevel.Trace)
{
Log.Trace("BlockCipher.Transform: input block {0}",
BitConverter.ToString(segment.Array, segment.Offset, segment.Count));
}
cs.Write(segment.Array, segment.Offset, segment.Count);
}
#endif
cs.FlushFinalBlock();
int result = (int)ms.Length;
var streamBuffer = ms.GetBuffer();
if (Log.Level <= LogLevel.Trace)
{
Log.Trace("BlockCipher.Transform: output {0} {1}",
result, BitConverter.ToString(streamBuffer, 0, result));
}
buffer.Rewind();
buffer.CopyFrom(streamBuffer, 0, result);
// Store the last ciphertext block as a next encryption IV.
System.Buffer.BlockCopy(streamBuffer, result - BlockSizeInBytes,
encryptionIV, 0, BlockSizeInBytes);
return result;
}
}
