"Remote user authentication is used to validate the legitimacy of a remote login user. Conventional user authentication
schemes are suited to solve the privacy and security problems for the single client/server architecture environment. However,
the use of computer networks and information technology has grown spectacularly. More and more network architectures are
used in multi-server environments. In this paper, we propose a new remote user authentication scheme. The scheme can be
used in multi-server environments. In our scheme, the system does not need to maintain any veriﬁcation table, and the users
who have registered in the servers do not need to remember different login passwords for various servers. In addition, our
scheme can also withstand replay and modiﬁcation attacks. Furthermore, it allows users to choose their passwords freely, and
a user can be removed from the system easily when"