Problem with file encryption.

public byte[] Transform(byte[] input, ICryptoTransform CryptoTransform)
       {
           // create the necessary streams
           MemoryStream memStream = new MemoryStream();
           CryptoStream cryptStream = new CryptoStream(memStream, CryptoTransform, CryptoStreamMode.Write);

           // transform the bytes as requested
           cryptStream.Write(input, 0, input.Length);
           cryptStream.FlushFinalBlock();

           // Read the memory stream and
           // convert it back into byte array
           memStream.Position = 0;
           byte[] result = memStream.ToArray();

           // close and release the streams
           memStream.Close();
           cryptStream.Close();

           // hand back the encrypted buffer
           return result;
       }