Efficient member authentication and authorization for a tree-based reliable multicast data distribution setup

To authenticate and authorize prospective members in a reliable multicast data distribution setup, the prospective members contact a central authority to obtain a "participation certificate" for the multicast session. The central authority authenticates each node and issues a digitally signed certificate to the node. Each certificate contains information specifying the manner in which the respective node is authorized to participate in the multicast session in addition to the respective node's public key. The nodes exchange their participation certificates with each other during session-establishment dialog to prove their identities and their authorization to participate. Each node verifies the rights of other nodes based on authorization information contained in the participation certificate received from the other node. Thus, a node is allowed to participate as a repair node only if it presents a participation certificate authorizing it to do so. Disruption in network operation is avoided by reducing the ability of malicious nodes to consume resources to the detriment of legitimate session members.