Enhancing Trust-Aware Routing by False Alarm Detection and Recovery

Insider packet drop attacks have become a serious threat to wireless sensor networks. To distinguish a packet dropped by inside attackers from network failures, each node will use a trust mechanism to evaluate its neighbor node's trustworthiness so it can send packets only to the trustworthy neighbors. One problem associated with such trust-aware routing algorithms is the false alarm which occurs when a good node's trust value goes down and being eliminated from the routing paths. This wastes network's resource and shortens network lifetime as most trust mechanisms seek to aggressively identify attackers at the cost of increasing false alarm rate. We propose a False Alarm DEtection and Recovery (FADER) technique to solve this problem. Instead of abandoning a node with low trust value from the network, we put it into an intermediate state between trusted and untrusted, known as suspicious node. We find alternate routing path for packet forwarding to guarantee the network's packet delivery rate. Meanwhile, we continue to send packet to the suspicious node and monitoring its trust value in order to determine whether the node is untrusted or a false alarm. We have conducted extensive OPNET simulations and the results demonstrate that the proposed FADER approach can improve the performance of the trust-aware routing protocol in terms of the network lifetime, the packet delivery rate, and many other routing performance measures. FADER is able to recover at least 60% of the false alarms without recovering any of the real attackers, this results in an average increase of about 40% in network's lifetime and can be as high as 83%.