Hybrid Identity Based Authenticated Key Exchange Protocols

The past decade has witnessed a surge in exploration of cryptographic concepts based on pairings over Elliptic Curves. In particular, Identity-Based Cryptographic protocols have received a significant amount of attention. We follow this trend with this paper, by describing and providing formal proof of security of a new protocol called Identity Based Authenticated Key Exchange (IBAKE). As the name implies, IBAKE provides mutually-authenticated Key Exchange, using identities as public credentials. The main ingredient of the construction is a hybrid approach, where we use two different Elliptic Curves, for authentication and session key generation respectively. Specifically, we use a combination of a super-singular and non-super-singular curves. The definitions of security we employ are natural adaptations and simplifications of the definitions proposed recently by Kolesnikov and Rackoff.