Detecting the Sybil attack in mobile ad hoc networks

Mobility is often a problem for providing security services in ad hoc networks. In this paper, we show that mobility can be used to enhance security. Specifically, we show that nodes that passively monitor traffic in the network can detect a Sybil attacker that uses a number of network identities simultaneously. We show through simulation that this detection can be done by a single node, or that multiple trusted nodes can join to improve the accuracy of detection. We then show that although the detection mechanism will falsely identify groups of nodes traveling together as a Sybil attacker, we can extend the protocol to monitor collisions at the MAC level to differentiate between a single attacker spoofing many addresses and a group of nodes traveling in close proximity.