eCK-security authenticated key agreement protocol based on CDH assumption

By far, the extended Canetti-Krawczyk (eCK) model still is one of strongest security model for authenticated key exchange (AKE) protocols. In this paper, a secure authenticated key agreement protocol named SAKA is analyzed in the model, the results show that the SAKA protocol does not support forward security which all key exchange protocol should satisfy. Furthermore, it does not meet security goals of the eCK model. In order to overcome all of above flaws, a variant of SAKA protocol is proposed based on Computation Diffie-Hellman assumption, and secure analysis shows that the new protocol has some good security properties including perfect forward secrecy and known session key excepting those desired security properties that SAKA has. Furthermore, fewer number of modular exponentiation indicates that the new scheme is more efficient.