Cryptanalysis and Improvement on a Remote User Authentication Scheme Using Bilinear Pairings

With the rapid development of Internet service, remote user authentication scheme becomes an important issue for practical applications. Over the past years, many remote user authentication schemes have been proposed. In 2006, Wang and Chai proposed a remote user authentication scheme using bilinear pairings. In this paper, we show that Wang-Chai's scheme is still vulnerable to impersonation attack and propose an improved scheme to resist this attack. The proposed scheme also provides both mutual authentication and session key agreement.