Abstract Mobile Ad hoc Networks (MANETs) are considered as t he most promising terminal networks in future wireless communications and characterized by flexibility, fa st and easy deployment, which make them an interest ing 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 agreem ent scheme to enable secure group communications, which adopts the Identity Based Broadcast Encryption (IBBE) methodol ogy. When a new Ad hoc network is constructed, the suggested scheme requires no message exchange to establish a group k ey 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 joi ns 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 gro up 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 .

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[26] Zhang L., Hu Y., and Mu N., An Identity(based Broadcast Encryption Protocol for Ad(hoc Networks, in Proceedings of The 9 th International Conference for Young Computer Scientists , USA, pp. 1619(1623, 2008. Yang Yang received her PhD degree in School of Communication Engineering from Xidian University of China in 2011. Now she is a lecturer in School of Math. And Computer Science of Fuzhou University. Her main research interests include network security and security protocol. Yupu Hu received his PhD degree in School of Communication Engineering from Xidian University of China in 2008. Now he is a professor in School of Telecommunication Engineering of Xidian University. His main research interests include information security and cryptogr aphy. Chunhui Sun is a PhD student in School of Communication Engineering of Xidian University. His main research interests include side channel attack and network security. Chao Lv is a PhD student in School of Communication Engineering of Xidian University. His main research interests include security protocol, RFID protocol and formal verification. Leyou Zhang received his PhD degrees in applied mathematics from Xidian University of China in 2009. Now he is an associate professor in the Department of Mathematical Sciences of Xidian University. His main research interests include security protocol and public key cryptography.