Authenticated Key Exchange Secure under the Computational Diffie-Hellman Assumption.

Abstract

Abstract. In this paper, we present a new authenticated key exchange(AKE) protocol and prove its security under the random oracle assumption and the computational Diffie-Hellman(CDH) assumption. In the extended Canetti-Krawczyk model, there has been no known AKE protocol based on the CDH assumption. Our protocol, called NAXOS+, is obtained by slightly modifying the NAXOS protocol proposed by LaMacchia, Lauter and Mityagin. We establish a formal security proof of NAXOS+ in the extended Canetti-Krawczyk model using as a main tool the trapdoor test presented by Cash, Kiltz and Shoup. Key words: authenticated key exchange, trapdoor test, computational Diffie-Hellman assumption, extended Canetti-Krawzcyk model 1