A Modified Dynamic ID-based Remote User Authentication Scheme

User authentication is the primacy safeguard of information security and network security. Password authentication is the most widely used means for remote user authentication. In this paper, we analyze a dynamic ID-based remote user authentication scheme and point out its security vulnerability. Once the adversary obtains a user's smart card, the adversary can masquerade as the legal user to login a remote server even without the user's password. Further more, an enhanced scheme is presented. The modified scheme can resist replay attack, forgery attack, guessing attack, insider attack and masquerade attack