Help for the encryption key 4.0

Hello anyone can tel me if my encryption key 4.0 is good ?

Code:

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public class Crypt {


    private final static Logger log = LoggerFactory.getLogger(Crypt.class);


    /**
    * Second byte of server packet must be equal to this
    */
    public final static byte staticServerPacketCode = 0x48;


    /**
    * Crypt is enabled after first server packet was send.
    */
    private boolean isEnabled;


    private EncryptionKeyPair packetKey = null;


    /**
    * Enable crypt key - generate random key that will be used to encrypt second server packet [first one is unencrypted]
    * and decrypt client packets. This method is called from SM_KEY server packet, that packet sends key to aion client.
    *
    * @return "false key" that should by used by aion client to encrypt/decrypt packets.
    */
    public final int enableKey() {
        if (packetKey != null)
            throw new KeyAlreadySetException();


        /** rnd key - this will be used to encrypt/decrypt packet */
        int key = Rnd.nextInt();


        packetKey = new EncryptionKeyPair(key);


        log.debug("new encrypt key: " + packetKey);


        /** false key that will be sent to aion client in SM_KEY packet */
        return (key ^ 0xCD92E4D7) + 0x3FF2CCC7;
    }


    /**
    * Decrypt client packet from this ByteBuffer.
    *
    * @param buf
    * @return true if decryption was successful.
    */
    public final boolean decrypt(ByteBuffer buf) {
        if (!isEnabled) {
            log.debug("if encryption wasn't enabled, then maybe it's client reconnection, so skip packet");
            return true;
        }


        return packetKey.decrypt(buf);
    }


    /**
    * Encrypt server packet from this ByteBuffer.
    *
    * @param buf
    */
    public final void encrypt(ByteBuffer buf) {
        if (!isEnabled) {
            /** first packet is not encrypted */
            isEnabled = true;
            log.debug("packet is not encrypted... send in SM_KEY");
            return;
        }


        packetKey.encrypt(buf);
    }


    /**
    * Server packet opcodec obfuscation.
    *
    * @param op
    * @return obfuscated opcodec
    */
    public static final int encodeOpcodec(int op) {
         
                return (byte)((op + 0xC6) ^ 0xD7); //4.0
    }
}

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nope, crypt is wrong