SWAN: A Secured Watchdog for Ad Hoc Networks

Summary Due to its nature, ad hoc networks are much more vulnerable to various attacks than traditional wired networks. Many solutions have been proposed in recent researches for the security of ad hoc networks. The watchdog mechanism, based on a node supervising all its local neighbors, is one of the basic security mechanisms used by these solutions. It is able to detect both malicious attacks and selfish behaviors without significant overhead. However, it has a high storage requirement, and itself needs to be secured against spoofing attacks which may badly affect the reputation systems depending on it. In this paper, we propose a secured and efficient supervision mechanism based on the watchdog technique called SWAN. In order to avoid spoofing attacks, we combine the techniques SUCV (Statistically Unique and Cryptographically Verifiable) and TESLA (Timed Efficient Stream Loss-Tolerant Authentication) to provide a lightweight broadcast message authentication to watchdog. Moreover, we also propose an efficient storage method to reduce the storage overhead required by watchdog. Our analysis and simulations show that our approach is both lightweight and robust.