Performance evaluation of anonymous routing protocols in MANETs

Mobile ad hoc networks require anonymous communications in order to thwart new wireless passive attacks; and to protect new assets of information such as nodes' locations, motion patterns, network topology and traffic patterns in addition to conventional identity and message privacy. In particular, in wireless ad hoc networks mobile nodes must rely on ad hoc routing to keep network functional for communication. The transmitted routing messages and cached active routing entries leave plenty of opportunities for eavesdroppers. To address the new challenges, several anonymous routing schemes have been proposed recently. However, in various network scenarios, how the different cryptographic operations impact the routing performance remains unclear. In this paper we investigate the impact from cryptographic operations needed for the anonymous features. The overhead considered includes both increased control packet size and prolonged processing delay. The protocols taken into account include ANODR, AnonDSR, ASR, MASK, and SDAR. We present results based on extensive simulation study. We use the standard/unprotected on-demand scheme AODV in the comparison to show how much cost is paid by each anonymous on-demand scheme. Our simulation study shows that various design choices in anonymous routing indeed trade performance with anonymity protection. We conclude that extensive performance study is needed to evaluate the practicality of any enhancement of these proposed schemes and any new anonymous routing schemes