Improved Dynamic ID-Based Remote User Authentication Scheme Using Smart cards

In 2004, Das presented a dynamic ID-based remote user authentication scheme using smart cards. Then in 2005, Liao showed that Das et al.´s scheme has some attacks and proposed a slight modification to their scheme to improve the weaknesses of it. This paper, however, will demonstrate that Liao et al.´s scheme has also some security flaws. Therefore, we propose an improved scheme to conquer their weaknesses. The improved scheme can enhance the security of Liao et al.´s scheme and is also efficient.