An Efficient Group Key Agreement Scheme for Mobile Ad-Hoc Networks

Mobile Ad-hoc Networks (MANETs) are considered as the most promising terminal networks in future wireless communications and characterized by flexibility, fast and easy deployment, which make them an interesting technology for various applications. Group communication is one of the main concerns in MANETs. To provide the secure group communication in wireless networks, a group key is required so that efficient symmetric encryption can be performed. In this paper, we propose a constant-round group key agreement scheme to enable secure group communications, which adopts the Identity Based Broadcast Encryption (IBBE) methodology. When a new Ad-hoc network is constructed, the suggested scheme requires no message exchange to establish a group key if the receivers' identities are known to the broadcaster, which is an advantage that outperforms most of the existing key agreement schemes. The proposed scheme can build a new group and establish a new group key with ease when member joins or leaves. In addition, our scheme is efficient in computation and only one bilinear pair computation is required for group members to obtain his/her session key. A highlight property of the scheme is that communication cost remains unchanged as group size grows. Furthermore, we show that the new scheme is proved secure without random oracle. Thus, the scheme can not only meet security demands of larger mobile Ad-hoc networks but also improve executing performance.