Identity-based Constant Round Group Key Exchange Protocol via Secret-Share

Group key management is one of the basic building blocks in securing group communication. A number of solutions to group key exchange have been proposed, but most of them are not scalable and require a number of rounds linear in the number of group members. We formally present a constant-round Identity-based protocol with forward secrecy for group key exchange, which is provably secure in the security model introduced by Bresson et al. Our protocol focuses on round efficiency and the number of communication round is only two. And, the protocol provides a batch verification technique, which simultaneously verifies the validity of messages from other group participants and greatly improves computational efficiency. Moreover, in our protocol, it is no necessary of always-online key generation center during the execution of the protocol compared to other Identity-based protocols. Key-Words: provable security, identity-based, group key exchange, constant round, secret-share.