Secure Multicast over Multihop Wireless Ad Hoc Networks

In this paper we address the problem of secure multicast of data streams over a multihop wireless ad hoc network. We propose a key management protocol that aims at solving problems that are specific to ad hoc networks such as mobility, unreliable links, and multihop communication cost. The main idea is to have group members actively participate to the multicast group security therefore reducing the communication and computation load on the source. We also extend the proposed basic secure multicast tree using multi-link capability combined with a k-out-of-N coding approach. Since the group security is distributed among the group members we propose a service right certificate to verify that a node is authorized to join the group and also corresponding revocation mechanism. We simulated our protocol within the ns-2 environment under various mobility, group size, and group dynamic scenarios. Our preliminary simulation results indicate that the communication cost and join delay of the protocol scale well when the group size and nodes mobility increase.