Exploiting channel-aware reputation system against selective forwarding attacks in WSNs

Wireless sensor networks (WSNs) are vulnerable to selective forwarding attacks that selectively drop a subset of the forwarding packets to degrade network performances. Due to unstable wireless channels, the packet loss rate between sensor nodes might be high, especially in hostile environments. Therefore, it is difficult to distinguish the malicious drop and normal packet loss. In this paper, we propose a Channel-aware deputation System (CRS) to identify selective forwarding misbehaviours from normal packet losses caused by poor channel quality or medium access collision. Specifically, CRS is based on normal packet loss estimation and neighbour monitoring. Each node maintains a reputation table to evaluate forwarding behaviours of its neighbours. Reputation value is determined by the deviation of the monitored packet loss rate and estimated normal loss rate. The nodes with reputation below a threshold are identified as misbehaving nodes and isolated from data forwarding paths. Furthermore, we develop weighted reputation propagation and integration functions to improve detection efficiency. Through theoretical analysis and extensive simulations, we demonstrate that CRS can accurately detect selective forwarding attacks and significantly improve the network throughput.