A New AKE Protocol with Stronger Security in the eCK Model

In this paper, we present a new authenticated key exchange (AKE) protocol, called NS+, which allows the adversary to reveal all the ephemeral secret information, especially including the Diffie-Hellman exponets, used for building one party's outputting message. We also prove the security of this protocol in the eCK model, under the random oracle assumption and the gap Diffie-Hellman (GDH) assumption. Our protocol is based on the NAXOS+ protocol proposed by Lee and Park and is of the same efficiency with it in terms of exponentiations.