A Scalable Multicast Key Management Scheme for Heterogeneous Wireless Networks

In the near future, many multicast services will involve wireless devices. Before these ser-vices can successfully be deployed, a security infrastructure that provides access control to the content must be developed. In wireless networks, where the error rate is high and the band-width is limited, the design of key management schemes should place emphasis on reducing the communication burden associated with key updating. A communication-efficient class of key management schemes are those that employ a tree hierarchy. However, these tree-based key management schemes do not exploit issues related to the delivery of keying information that provide opportunities to further reduce the communication burden of rekeying. In this paper, we propose a method for designing multicast key management trees that match the network topol-ogy associated with mobile wireless applications. By matching the key management tree to the cellular network topology and localizing the transmission of keying information, the proposed key management scheme significantly reduces the communication burden of rekeying. Further, in the wireless scenario, the issue of user handoff between base stations may cause user reloca-tion on the key management tree, which introduces extra rekeying overhead. We address th