SGOR: Secure and scalable geographic opportunistic routing with received signal strength in WSNs

Wireless sensor networks (WSNs) are inherently susceptible to attacks as malicious nodes can disrupt the communication from any other node to the sink. To address a wide range of attacks, we propose a novel and comprehensive approach called Secure and Scalable Geographic Opportunistic Routing with received signal strength (SGOR), satisfying the requirements of both security and scalability in WSNs. Unlike most of previous secure protocols relying on infrastructure like anchor nodes, a distributed location verification algorithm is presented to utilize the received signal strength to address the location spoofing attack. As one of opportunistic geographic routings, SGOR provides the property of robustness by taking full advantage of the broadcast nature of wireless channels, and scalability for being inherited from geographic routing. Moreover, an ambient-sensitive trust model is proposed to defend against more kinds of attackers in SGOR. The theoretical results are given to demonstrate the effectiveness and robustness of SGOR to survive more severe attacks. In extensive simulations, we compare SGOR with four other representative protocols. The results show that SGOR achieves about two times higher packet delivery rate with acceptable overhead, particularly in large and highly hostile networks.