A Peer-based Recovery Scheme for Group Rekeying in Secure Multicast

The Logical Key Hierarchy (LKH) provides a scalable and efficient way to distribute session keys to authorized group members in secure group (multicast) communication. However, because multicast is a best-effort service, it requires additional mechanism to ensure that every member receives the rekey information. To solve this problem, several FEC-based schemes have been proposed. Although these schemes significantly enhance the reliability of the rekey transmissions, they require significant additional resources at the key server. In this paper we propose a distributed scheme for recovering lost rekey packets. Our scheme allows each member to contact other members to get the missing packets during rekey events, thus avoiding the extra computation and bandwidth resources at the key server. We compare our scheme with a well-known FEC scheme with respect to latencies experienced by receivers in reasonably large groups. Results show that our scheme yields lower average and 95thpercentile latencies than the FEC-based scheme across several operating regimes.