A Protocol for End-to-End Key Establishment During Route Discovery in MANETs

An end-to-end shared secret key between two distant nodes in a mobile ad hoc network (MANET) is essential for providing secure communication between them. However, to provide effective security in a MANET, end-to-end key establishment should be secure against both internal as well as external malicious nodes. An external malicious node in a MANET does not possess any valid security credential related to the MANET, whereas an internal malicious node would possess some valid security credentials related to the MANET. Most of the protocols for end-to-end key establishment in MANETs either make an unrealistic assumption that an end-to-end secure channel exists between source and destination or use bandwidth consuming multi-path schemes. In this paper, we propose a simple and efficient protocol for end-to-end key establishment during route discovery (E2-KDR) in MANETs. Unlike many other existing schemes, the protocol establishes end-to-end key using trust among the nodes which, during initial stage, is established using public key certificate issued by an off-line membership granting authority. However, the use of public key in the proposed protocol is minimal to make it efficient. Since the key is established during route discovery phase, it reduces the key establishment time. The proposed protocol exploits mobility to establish end-to-end key, and provides comprehensive solution by making use of symmetric keys for protecting routing control messages and end-to-end communication. Moreover, as the end-to-end keys are established during route discovery phase, the protocol is on-demand and only necessary keys are established, which makes the protocol storage scalable. The protocol is shown to be secure using security analysis, and its efficiency is confirmed by the results obtained from simulation experiments.