Efficient and Secure Multicast in WirelessMAN: A Cross-Layer Design

Effectively adding security measures to a multicast service is an intriguing problem, especially when the service is deployed in a wireless setting. Next generation IEEE 802.16 standard WirelessMAN networks are a perfect example of this problem, and the latest draft specification of the standard includes a secure protocol solution called Multicast and Broadcast Rekeying Algorithm (MBRA). In this paper, the authors expose the security problems of MBRA, including non-scalability and omission of backward and forward secrecy, and propose new approaches, ELAPSE and ELAPSE+, to address these problems. In particular, ELAPSE+ makes use of membership and mobility information gathered in the application layer to augment the adaptive group management in the MAC layer.