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.