Paper 2004/163

On the Weaknesses and Improvements of an Efficient Password Based Remote User Authentication Scheme Using Smart Cards

Manoj Kumar

Abstract

In 2002, Chien et al. proposed an efficient remote user authentication scheme using smart cards. Later, in 2004, W. C. Ku and S. M. Chen pointed out some attacks on Chien et al.’s scheme. W. C. Ku and S. M. Chen also proposed a modified scheme to prevent the attacks on Chien et al.’s scheme. This paper discusses the security of the W. C. Ku and S. M. Chen’s scheme. This paper aims to show that the modified scheme is still vulnerable to the password guessing attack and the insider attack.