Dynamic trust establishment in emergency ad hoc networks

This paper proposes a dynamic trust establishment protocol that enables the nodes of an ad hoc network to establish security associations among each other in a distributed and peer-to-peer manner. The basis of the protocol is a node-tonode security handshake using a network-wide key that every node is preconfigured with. This way a security association is established between the involved nodes. The information regarding such an association is propagated to the rest of the trusted nodes, resulting in the formation of a secure network overlay. The protocol is dynamic in the sense that the nodes keying material is periodically renewed by a set of leader nodes in order to enhance the system security. Although generic, our protocol is best suited to emergency ad hoc networks, where the aforementioned assumptions about the node preconfiguration and the reliability of the leader nodes are applicable. The proposed protocol extends previous work on authority-based trust establishment schemes by using a renewal process of the nodes' keying material and by being independent of the underlying routing protocol and the nodes' communication capabilities. Simulation results show that the performance of the protocol depends directly on the network connectivity, the number of leader nodes and the node mobility level.