Cryptanalysis on Improved Remote User Authentication Scheme Preserving User Anonymity

Remote user authentication using smartcards is the most widely used scheme for a valid user to login to a remote server and to access the services provided by the server over insecure channels. Due to the convenience, secure storage, and secure computation of smartcards, many smartcard-based remote authentication schemes have been proposed. Most of these schemes have the following good properties: the server has no password table; users can freely choose their own passwords; it demands only low communication and computation cost; mutual authentication is provided between a user and a server.