Towards Efficient and Secure Rekeying for IEEE 802.16e WiMAX Networks

In this paper, we study the rekeying issue in IEEE 802.16e WiMAX networks. The existing rekeying scheme the Multicast and Broadcast Rekeying Algorithm (MBRA) unicasts new keys to each subscriber station (SS). This scheme does not scale well since it incurs large communication overhead when the number of SSs increase. In our work, first we propose a general tree-based rekeying scheme, which is more efficient than the MBRA. We then formulate an optimization problem to determine the optimal tree structure for a given number of SSs. Furthermore, we design a novel and efficient rekeying scheme for WiMAX networks. Our new rekeying scheme utilizes efficient security primitives and application features of WiMAX networks. Both analysis and performance evaluation show that the new rekeying scheme can significantly reduce communication overhead.