Secure multicast groups on 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 dynamic multicast group management protocol that aims at solving problems that are specific to ad hoc networks such as mobility, unreliable links, and cost of multihop communication. The main idea is to have group members actively participate to the security of the multicast group, therefore reducing the communication and computation load on the source. 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 a corresponding revocation mechanism. We simulated our protocol within the ns-2 environment under various mobility, group size, and group dynamic scenarios. Our simulation results indicate that the communication cost and join delay of the protocol scale well when the group dynamic and nodes mobility increase. We have implemented the basic protocol in our ad hoc network testbed. We also proposed an extension to the basic secure multicast tree using multi-link capability combined with a k-out-of-N coding approach.