I've written code a little easier to understand, and hope it will give some response... Key and iv are double checked and correct data is received as it was sent. public byte[] SecureSerialize(byte[] key, byte[] iv) { byte[] streamBuffer = new byte[BufferSize]; MemoryStream ms = new MemoryStream(streamBuffer); ms.WriteByte((byte)encrypted); RijndaelManaged rij = new RijndaelManaged(); CryptoStream cs = new CryptoStream(ms, rij.CreateEncryptor(key, iv), CryptoStreamMode.Write); BinaryFormatter bf = new BinaryFormatter(); bf.Serialize(cs, this); SHA1Managed hashAlg = new SHA1Managed(); byte[] hash = hashAlg.ComputeHash(streamBuffer, 0, (int)ms.Position); bf.Serialize(ms, hash); byte[] returnBuffer = new byte[(int)ms.Position]; Array.Copy(streamBuffer, 0, returnBuffer, 0, (int)ms.Position); return returnBuffer; } public static UdpMessage SecureDeserialize(byte[] msg, byte[] key, byte[] iv) { MemoryStream ms = new MemoryStream(msg); byte enc = (byte)ms.ReadByte(); RijndaelManaged rij = new RijndaelManaged(); CryptoStream cs = new CryptoStream(ms, rij.CreateDecryptor(key, iv), CryptoStreamMode.Read); BinaryFormatter bf = new BinaryFormatter(); UdpMessage message = (UdpMessage)bf.Deserialize(cs); // <<<----This fails message.encrypted = (Encryption)enc; SHA1Managed hashAlg = new SHA1Managed(); byte[] calculatedHash = hashAlg.ComputeHash(msg, 0, (int)ms.Position); byte[] msgHash = (byte[])bf.Deserialize(ms); for (int i = 0 ; i < calculatedHash.Length ; i++) if (calculatedHash[i] != msgHash[i]) throw new CryptographicException("Hash missmatch"); return message; } Regards 3ddA
