Three-Party Password-Based Authenticated Key Exchange with Forward-Security

Most password-authenticated key exchange schemes in the literature provide an authenticated key exchange between a client and a server based on a pre-shared password.With a rapid change in modern communication environments,it is necessary to construct a secure end-to-end channel between clients,which is a quite different paradigm from the existing ones.The authors propose a provably forward-secure three-party password-based authenticated key exchange protocol in which two communication entities can authenticate each other and establish a session key through the assistance of an authentication server.The proposed protocol is efficient both in computational cost and in communication cost when compared with previous solutions and thus attractive in resources-constrained environment.The security of the proposed scheme has been proven in the random oracle model under the password chosen-basis Gap Diffie-Hellman assumption.