Abstract
Wireless sensor networks are becoming a critical computational infrastructure, in which the communication between nodes needs to be protected from eavesdropping and tampering. Symmetric key cryptography is the fundamental technique being used. The protocols in this domain suffer from one or more of the problems of weak security guarantees if some nodes are compromised, lack of scalability, high energy overhead for key management and increased end-to-end data latency. In this paper, we propose a protocol called SECOS that mitigates these problems. SECOS divides the sensor field into control groups each with a control head. Data exchange between nodes within a control group happens through the mediation of the control head which provides the common key. The keys and the control heads are changed periodically to enhance security. SECOS enhances the survivability of the network by handling failures of control nodes. The experiments based on a simulation model show 7 times reduction in energy overhead and 50% reduction in latency compared to the state-of-the-art protocol, SPINS. We also provide an analytical derivation of the optimal control group size that operates under the resource constraints and minimizes energy consumption.
