The Research Of Group Key Management In Ad Hoc Networks

Ad Hoc network is a collection of wireless mobile nodes which are able to communicate with each other in the absence of any network infrastructure. Nodes in Ad Hoc network can move without any restriction, join or exit network dynamically. All the nodes in Ad Hoc are equal in status, each of them plays the role of host and router. Self-organized, openings and highly dynamic topology make Ad Hoc suitable for certain condition without fixed network facilities such as battlefield communication and emergency rescue.However, these fundamental properties make Ad Hoc face more serious security threats than traditional network. Traditional security mechanism can not be use directly in Ad Hoc network due to its distributed layout. Currently security measures research in Ad Hoc network focus on key management, secure routing and intrusion detection etc. As the foundation of security measure in Ad Hoc, key management shoud be paid more attention to.In this paper we mainly discuss group key management in Ad Hoc network. First, we introduce the basic concepts, origin, structure, features and applications of Ad Hoc network. Based on the introduction we analyse its security weakness and potential attack, detail its security target, and expound several aspects of its security strategy. Then we study key management of group communication in Ad Hoc network and research two typical group key management plan, explaining their advantages and disadvantages. By taking RSA and threshold cryptography, verified secret sharing as tool and combining with distributed system we propose a new group key management scheme. In the new scheme, system key has been distributed among members thus attack on the key becomes more difficult than before, so the safety of group can be improved efficiently. Through the introduction of verified secret sharing, we prevent cheat behaviour of group member during the process of system key combination successfully. Strategy of group key refresh makes communications be forward-secret and backward-secret.Compared with the existing plan, the new scheme is more adaptable to Ad Hoc network with its dynamic topology, limited nodes and distributed management. On one hand, the new scheme reduces the load of key management effectively, on the other hand, it improve the performance and reliability of Ad Hoc network.