ZigBee is used as a low power and low rate wireless sensor network. Many applications utilize it for data transfer. It provides some security options, including message authentication, message encryption and defense against replay attack. The security algorithms used in the ZigBee are run for each packet transfer when the security mode is on. This study tested the impact of message authentication over the network performance in terms of the throughput and data packet delivery ratio. The message authentication leads to performance degradation for the network. The blocks of the message are encrypted by using Advanced Encryption Standard (AES) algorithm for authenticating in CBC-MAC algorithm. The performance of the network is improved over the original state when AES algorithm is replaced by MKP-AES algorithm and DMAC algorithm is used to parallelize the authentication. MKP-AES is tested within two and three secret keys. The network is simulated using NS-2 to measure the performance improvement.