Cluster-based Group Key Agreement for Wireless Ad hoc Networks

The establishment of a group key in wireless ad hoc networks is considered a difficult task from both an algorithmic and computational point of view. The reason is the special nature and the constraints posed by these networks. In this paper, we present an efficient group key agreement protocol which is particularly suitable for energy constrained, dynamically evolving wireless ad hoc networks. The topology of the network is reflected in a structure composed by small clusters. This clustering allows the synchronous execution of efficient tripartite key agreement protocols based on pairings. The required computations are simple for the devices to implement, the size of the exchanged messages is minimum and the storage memory required in every node is very small. The proposed protocol also avoids the usage of a TTP or a central authority and achieves a good energy balance. Finally, we compare the communication/computation complexity of our protocol with previously known protocols and show that it compares favourably with them.