Secure Multicast in WiMAX

Multicast enables efficient large-scale content distribution and has become more and more popular in network service. Security is a critical issue for multicast because many applications require access control and privacy. This issue is more sensitive to wireless network, which is lack of physical boundaries. IEEE 802.16 is the standard for next generation wireless network, which aims to provide the last mile access for Wireless Metropolitan Area Network (WirelessMAN). Multicast is also supported in IEEE 802.16, and a Multicast and Broadcast Rekeying Algorithm (MBRA) was proposed in the standard as an optional function for secure multicast. However, this algorithm does not provide backward and forward secrecy. It is not scalable to a large group either. This paper reviews the above two deficiencies of MBRA and proposes revision to address these problems for Intra-BS multicast. We also propose algorithms for secure multicast in different scenarios of WirelessMAN besides its basic schema, including Inter-BS multicast, multicast for mesh network, and multicast during handover.