An enhanced privacy preserving remote user authentication scheme with provable security

Very recently, Kumari et al. proposed a symmetric key and smart card-based remote user password authentication scheme to enhance Chung et al.'s scheme. They claimed their enhanced scheme to provide anonymity while resisting all known attacks. In this paper, we analyze that Kumari et al.'s scheme is still vulnerable to anonymity violation attack as well as smart card stolen attack. Then we propose a supplemented scheme to overcome security weaknesses of Kumari et al.'s scheme. We have analyzed the security of the proposed scheme in random oracle model which confirms the robustness of the scheme against all known attacks. We have also verified the security of our scheme using automated tool ProVerif. Copyright © 2015 John Wiley & Sons, Ltd.