Topology-aware key management schemes for wireless multicast

In secure multicast applications, key management must be employed to provide access control to the multicast content. In wireless networks, where the error rate is high and the bandwidth is limited, the design of key management schemes should place emphasis on reducing the communication burden associated with key updating and improving the reliability of key distribution. The topology-matching key management (TMKM) scheme has been proposed to reduce the communication burden associated with rekeying by matching the key tree to the network topology and localizing the transmission of rekeying messages. This scheme, however, is only suitable for homogeneous networks where mobiles users are uniformly distributed in the service area and experience similar delay and transmission error rates. In this paper, we present an improved topology-aware key management scheme that is suitable for a large-scale cellular wireless network where the heterogeneity of the network is taken into consideration. The proposed scheme not only reduces the communication overhead, but also improves the reliability of the key distribution.