Security Analysis and Enhancement of a Dynamic Identity Based Authentication Scheme Using Smart Cards

Remote user authentication is an important and efficient method to ensure security for many network-based application systems. So far, several dynamic identity based authentication schemes have been proposed to protect the user´s anonymity. Recently, Sood pointed out the security weaknesses of a dynamic identity based authentication scheme, which was proposed by Wang et al. presented an improved scheme. However, in this paper, we demonstrate that Sood´s scheme cannot resist leak of verifier attack, impersonation attack and server spoofing attack. Furthermore, Sood´s scheme cannot achieve mutual authentication between the user and the server. Consequently, in this paper, we propose a new dynamic identity based user authentication scheme using elliptic curve cryptosystem to resolve all the aforementioned problems.