More secure remote user authentication scheme

Recently, Yoon and Yoo proposed a remote user authentication scheme which is an improvement on Lee–Kim–Yoo’s method. However, we find out that Yoon–Yoo’s scheme easily reveals a user’s password and is vulnerable to both masquerading user attack and masquerading server attack. Yoon–Yoo’s scheme is also exposed to stolen verifier attack, because it has to maintain a user database in a remote server. This paper proposes a new remote user authentication scheme that resolves all aforementioned problems, while keeping the merits of Yoon–Yoo’s scheme.