UMTS is the most popular third-generation mobile phone system at
present, and the UMTS AKA is his authentication and key agreement protocol.
There are some weaknesses in the existed UMTS AKA protocol, such as
synchronization question, storage overhead, insecurity with leakiness authentication
vector, and weakness in mutual authentications. In this paper, we
use the concept of proxy key to design a more secure and more efficient UMTS
AKA protocol. Our protocol not only resists above-mentioned drawback of
the original UMTS AKA protocol on the security, but also can improve the
performance of UMTS AKA protocol, including the computational overhead,
storage overhead, and communication overhead.