Remote login password authentication scheme using tangent theorem on circle in a multi-server environment

In this paper we propose a remote password authentication scheme based on a circle. This scheme is simple and practically feasible in a multi-server environment. In this scheme, we use some simple tangent theorem like secant tangent theorem and a strong one way function to authenticate the user and the server. Furthermore, a legal user can freely choose and change his password using his smart card. The security of this scheme depends on the tangent points located in a plane associated with the circle and tangent line.