Efficient Key Management Scheme for Secure Application Level Multicast

Application layer multicast (ALM) was proposed as a practical alternative to overcome the difficulty of large scale deployment of IP multicast. An important number of solutions were yet proposed for constructing overlay networks, however only a limited effort was given to security issues in ALM. In this paper we propose an efficient key management protocol, called transition key scheme (TKS), that can be applied within any ALM solution. Our scheme reduces the key management overhead in case of highly dynamic membership sessions by using a unique TEK (traffic encryption key), for the group, and a small number of transition keys to temporally manage members who recently joined the group. Simulation results confirm that TKS reduces significantly key management overhead, compared to other existing ALM key management protocols.