Impersonation Attack on a Dynamic ID-Based Remote User Authentication Scheme Using Smart Cards

Recently, Das et al. proposed a dynamic ID-based verifierfree password authentication scheme using smart cards. To resist the IDtheft attack, the user’s login ID is dynamically generated and one-time used. Herein, we demonstrate that Das et al.’s scheme is vulnerable to an impersonation attack, in which the adversary can easily impersonate any user to login the server at any time. Furthermore, we also show several minor weaknesses of Das et al.’s scheme. key words: dynamic ID, impersonation attack, password authentication, reparability, smart card