Group Authenticated Key Exchange Protocol For Wireless Mobile Environment

Diversified computable equipments and the rapid changes in digital communi-cation provide a good platform for the group applications such as digital conferencesystems, text-based communication tools and cooperative work systems. Users areprovided with convenient and reliable group applications, developers need to care-fully consider the security issues.Group key establishment protocol is a fundamentalsecurity component for group-oriented applications.Group key establishment protocol is an interactive process involving two or moreparticipants. Protocol can generate a shared session key for all participants and thiskey can be used in follow-up of the security mechanism. Group key establishmentprotocol is usually divided into two categories: group key distribution protocol andthe group key exchange protocol.This paper proposes two Group Authenticated Key Exchange protocols: protocolI and protocol II, which are applied to mobile wireless environment.Protocol I embraces features as follows: firstly, the asymmetry of computation,which means that our protocol allows a powerful node to shoulder more computationalburdens and the others can perform less. So our protocol can be better adapted toa wireless mobile environment, a computationally asymmetric one. Secondly, apartfrom the basic security of the session key, our protocol takes the insider attack intoconsideration. thirdly, the protocol is shown provably secure in formal model.Protocol II embraces features as follows: Firstly, robustness. Robustness refersto the loss of the individual participants during execution, which will not affect theoperation of the protocol. In the wireless environment, it is common to get participantslost in the process of protocol, and the robustness of the protocol should be taken intokey consideration. Secondly, as the same as protocol I, in addition to the basic security of the generated key, protocol II also considers insider attacks.So far, protocol I is the first group authenticated key exchange protocol for wire-less mobile environment, with a formal security proof and taking insider attacks intoaccount. Protocol II is the first authenticated group key exchange protocol referring tothe robustness and insider attacks.