摘要

With the continue evaluation of mobile devices in terms of the capabilities and services, security concerns increase dramatically. To provide secured communication in mobile client-server environment, many user authentication protocols from pairings have been proposed. In 2009, Goriparthi et al. proposed a new user authentication scheme for mobile client-server environment. In 2010, Wu et al. demonstrated that Goriparthi et al.'s protocol fails to provide mutual authentication and key agreement between the client and the server. To improve security, Wu et al. proposed an improved protocol and demonstrated that their protocol is provably secure in random oracle model. Based on Wu et al.'s work, Yoon et al. proposed another scheme to improve performance. However, their scheme just reduces one hash function operation at the both of client side and the server side. In this paper, we present a new user authentication and key agreement protocol using bilinear pairings for mobile client-server environment. Performance analysis shows that our protocol has better performance than Wu et al.'s protocol and Yoon et al.'s protocol. Then our protocol is more suited for mobile client-server environment. Security analysis is also given to demonstrate that our proposed protocol is provably secure against previous attacks.