An improvement of Xu et al.'s authentication scheme using smart cards
Sandeep K. Sood, Anil K. Sarje, Kuldip Singh · 2010
In 2009, Xu et al. found that Lee et al.'s [3] scheme is vulnerable to offline password guessing attack. Xu et al. also demonstrated that Lee and Chiu's [4] scheme is vulnerable to forgery attack. Furthermore, Lee and Chiu's scheme does not achieve mutual authentication and thus can not resist malicious server attack. Therefore, Xu et al. proposed an improved scheme that inherits the merits of Lee et al.'s and Lee and Chiu's schemes and resists different possible attacks. However, we found that Xu et al.'s scheme is vulnerable to forgery attack. This paper presents an improved scheme to resolve the aforementioned problem, while keeping the merits of Xu et al.'s scheme.