Key Distribution in Mobile Ad Hoc Networks Based on Message Relaying

Securing wireless mobile ad hoc networks (MANETs) is challenging due to the lack of centralized authority and poor connectivity. A key distribution mechanism is central to any public key management scheme. We propose a novel key distribution scheme for MANETs that exploits the routing infrastructure to effectively chain peer nodes together. Keying material propagates along these virtual chains via a message relaying mechanism. We show that the proposed approach results in a key distribution scheme with low implementation complexity, ideally suited for stationary ad hoc networks and MANETs with low to high mobility. The proposed scheme uses mobility as an aid to fuel the rate of bootstrapping the routing security, but in contrast to existing schemes does not become dependent on mobility. The key dissemination occurs completely on-demand; security associations are only established as needed by the routing protocol. We show through simulations that the scheme's communication and computational overhead has negligible impact on network performance.