We propose and analyze a scalable and efficient cluster-based group key management protocol for secure group communications in mobile ad hoc networks. For scalability and dynamic reconfigurability; we take a cluster-based approach by which group members are broken in to cluster-based subgroups and leaders in subgroups securely communicate with each other to agree on a group key in response to membership change and member mobility events. We show that secrecy requirement for group communication is satisfied. Further, there exists an optimal cluster size that minimizes the total network communication cost as a result of efficiently trading inter-regional vs. intra-regional group key management overheads. We give an analytical expression of the cost involved which allows the optimal cluster size to be identified, when given a set of parameter values characterizing a group communicating system in mobile ad hoc networks.

Many mobile wireless applications nowadays are based on....