Security problems of a “more secure remote user authentication scheme”

Smart card is widely accepted device which is used as a second authenticating factor in remote user authentication schemes. Kim-Chung proposed a remote user authentication scheme and they claimed that their scheme resists various security problems which were present in previous schemes such as offline leakage of password, stolen verifier attack, chances of masquerading the entities of the scheme. However, we come across some of the security loopholes in Kim-Chung's scheme which we will discuss in this paper.