An efficient and secure protocol for sensor network time synchronization

The emerging field of wireless sensor networks offers countless possibilities for achieving large scale monitoring in a distributed environment. These networks of resource constrained nodes require time synchronization for various distributed operations, but traditional protocols have significant overhead and rapidly deplete battery power. This paper addresses the challenges of sensor network engineering by proposing an efficient and secure time synchronization protocol named Tempest. The protocol reduces overhead and conserves power by using passive participation. It allows a node to infer the canonical time by simply overhearing the communication of its neighbors. It also authenticates protocol messages, and uses cross-layer control to manipulate counters in an encryption module to prevent attacks. Its implementation uses only minimal processing and negligible state, while an emphasis on reuse and modularity reduces code size. The protocol is implemented on embedded sensor node hardware, and is shown to substantially reduce overhead while maintaining the synchronization accuracy of recent related work. This reduction in overhead saves valuable energy, extending the lifetime of each sensor node and the lifetime of the sensor network itself.