One-round identity-based key exchange with Perfect Forward Security

Identity-based authenticated key exchange (IBAKE) protocol is one of the most important cryptographic primitives that enables two parties using their identities to establish their common secret keys without sending and verifying public key certificates. Recently, many works have been dedicated to design efficient and secure IBAKE protocols without bilinear pairings which need the heavy computational cost. Unfortunately, most of the proposed protocols cannot provide Perfect Forward Security (PFS) which is a major security goal of authenticated key exchange protocols. In this paper we present an efficient and provably secure IBAKE protocol with PFS. Our protocol relies on the technique known as the concatenated Schnorr signature and it could be viewed as a variant of the protocol proposed by Fiore et al. in 2010. By using the Canetti-Krawczyk security model, we prove that the protocol is secure with PFS under the Computational Diffie-Hellman assumption in the random oracle model. The protocol is of interest since it offers a remarkable combination of advanced security properties and efficiency and its security proof is succinct and intelligible.