Research On Group Key Management For Manet

A mobile ad hoc network (MANET) is a new type of wireless network, the characteristic of it is self-organized and without the support of fixed infrastructures, which makes it the hotspot of wireless network. As its characteristic, MANET is developed for wide application, such as military, commerce, urgent service and family purpose. Security is essential for MANET, and it is also one of the hot areas in MANET research nowadays. In MANET, the group key management is the basis of multicast, and it is also the basis of member identity authentication and secure routing. Thereby,The research of group key management is significant.The thesis first focus on the characteristics and security requirements of MANET, analyzes the limitations of existing work. We propose a novel hierarchical group key management framework based on the Identity-Based Cryptography (IBC) and threshold secret sharing mechanism. Aim at the rekeying problem for member change; we propose two group rekeying algorithms under the group key management framework, which sloves the problem of member change. The performances of the algorithms are studied using the network simulator (OPNET Modeler); the results demonstrate the algorithms are scalable and adaptable.The major contributions of the thesis include:1. We propose a hierarchy group key management framework based on threshold secret sharing mechanism. In this framework, the generation and rekey of TEK is defined. We make use of the partial distributed framework for group key collaborate and group rekeying in the upper level and the centerial key management framework is adopted in the second level. The framework is adaptive to frequent topology changes, robustness and scalability, also it avoids single point of failure.2. In order to meet the forward-secrecy and backward-secrecy polices, any change in the membership should rekey the TEK. Based on our group key management framework, Key Matrix based Group Rekey Algorithm (KMGR) is proposed for common membership change. The KMGR make use of the 2-dimensional character of matrix and is suitable for MANET. The group Rekeying is reduced as a series of row and column multicast, the algorithm is suitable for MANET, which possesses characteristics of frequently changing network topology, limited bandwidth and short-lived connection.3. Due to the membership change of Group Control Node, a novel Rekeying algorithm of group control key is proposed in the thesis, which is based on the trust model of IBC. Instead of all GCNs collaborate the GCK, we choose one node whose connexity is max, as a result, the trust model of IBC is used repeatedly and the message amount is reduced. The performances of the algorithm is studied using network simulator (OPNET), and the simulation results demonstrate the superiority of the algorithm over existing algorithm and protocols in terms of group key communication and delay.