A novel authenticated group key agreement protocol for mobile environment

An authenticated group key agreement protocol allows a group of parties to authenticate each other and then determine a group key via an insecure network environment. In 2009, Lee et al. first adopted bilinear pairings to propose a new nonauthenticated group key agreement protocol and then extend it to an authenticated group key agreement protocol. This paper points out that the authenticated protocol of Lee et al. is vulnerable to an impersonation attack such that any adversary can masquerade as a legal node to determine a group key with the other legal nodes and the powerful node. This paper shall employ the short signature scheme of Zhang et al. to propose a new authenticated group key agreement protocol. The short signature scheme of Zhang et al. is proven to be secure against the adaptive chosen-message attacks in the random oracle model, so the proposed protocol can withstand the possible attacks. Besides, compared with the authenticated protocol of Lee et al., the proposed protocol is more secure and efficient.