Abstract or Summary:
We study how to generalize a key agreement and password authentication protocol on the basis of the well known hard problems such as a discrete logarithm problem and a Diffie-Hellman problem. The key agreement and password authentication protocol is necessary for networked or internetworked environments to provide the user knowledge-based authentication and to establish a new cryptographic key for the further secure session. The generalized protocol implies in this paper to require only weak constraints and to be generalized easily in any other cyclic groups which preserve two hard problems. The low entropy of password has made it difficult to design such a protocol and to prove its security soundness. In this paper, we devise a protocol which is easy to be generalized and show its security soundness in the random oracle model. The proposed protocol reduces the constraints extremely only to avoiding a smooth prime modulus. Our main contribution is in solving the password's low entropy problem in the multiplicative group for the generalization.