An Efficient User Authentication Protocol using Smartcard

Due to the increasing interest and demands of user privacy, remote user authentication schemes using smart card has been researched in active. Recently, a lot of suggestion have been made in order to provide user`s anonymity and trace a malicious user. In 2008, Kim et al. proposed a traceable anonymity authentication scheme. In 2009, Choi et al. pointed out that Kim`s protocol was insecure against outsider attacker and proposed an improved scheme. But Kim`s and Choi`s schemes fail to provide the user`s anonymity or compute some values in the protocol. In this paper, we analyse those problems and suggest two improved schemes to resolve those problems.