Attacks and Solutions on the Quan et al.’s Smart Card Based Remote User Authentication with a Key Agreement Scheme

Abstract

Recently, Quan et al. proposed a smart card based user authentication scheme to conquer the existing defects in An’s scheme. In their paper, they claimed that their proposed scheme could resist various attacks. However, by analysing their scheme, we demonstrate that it still suffers from a traceable attack and an off-line password guessing attack. To erase the weaknesses and enhance the security, we then suggest some modification in their scheme. Compared with Quan et al.’s and other related schemes, our modified one performs better in terms of security.