Various wireless communication technologies have been developed and deployed because of the increasing access requirements. As a result, it brings a great challenge for designing seamless handover authentication protocols in wireless networks, especially in ensuring security and efficiency. The innocent users in wireless networks hope that the Mobile Internet Service Provider can not only provide efficient Internet access, but also protect their privacy. To provide trust and privacy preserving services, in this paper, we propose a new handover authentication protocol for wireless networks. Specifically, the new protocol provides user anonymity and untraceability, and it achieves high efficiency. Compared with other handover authentication protocols, our proposed mechanism achieves outstanding features of security and efficiency.