Further Improvement of An Authentication Scheme with User Anonymity for Wireless Communications

Seamless roaming is highly desirable for wireless communications, and security such as authentication and privacy preserving of mobile users is challenging. Recently, Wu et al. and Wei et al. proposed two authentication schemes that guarantee user anonymity in wireless communications, respectively. However, Kang et al. pointed out some security flaws of Wu et al.’s and Wei et al.’s authentication schemes and showed how to overcome the problems regarding anonymity and the forged login messages. In this paper, we will show that Kang et al.’s improved scheme still did not provide user anonymity as they claimed and give a further improvement to fix the problem without losing any features of the original scheme.