A strongly secure identity-based authenticated group key exchange protocol

In group key exchange(GKE) protocols, a shared secret key is established among a group of members for cryptographic use over a public network. An identity-based protocol is preferred to that under the employment of traditional public key infrastructure(PKI), since identity-based cryptosystem can simplify public key management procedure. In ASIACCS 2011, a security model for GKE protocol called EGBG model was proposed. The EGBG model takes ephemeral secret key leakage attack into consideration. Until now, there is no ID-based GKE protocol secure in the EGBG model. In this paper, we propose an identity-based GKE protocol. Its AKE-security with KCIR and full forward secrecy, MA-security with KCIR and its contributiveness are proven in the EGBG model. The proposed protocol does not involve NAXOS trick, which does not resist side channel attack and thus it provides stronger security guarantee. It achieves mutual authentication without applying signature, which makes the protocol more practical.