Secure Time Synchronization against Malicious Attacks for Wireless Sensor Networks

Wireless sensor networks (WSNs) have emerged as an interesting research area in the last few years. The applications envisioned for such networks require collaborative execution of a distributed task amongst a large set of sensor nodes. The collaborative execution is realized by exchanging messages that are time-stamped using the local clocks on the nodes. Hence, time synchronization becomes indispensable in such distributed systems. For years, protocols such as network time protocol (NTP) have kept the clocks of networked systems in perfect synchronization. However, wireless sensor networks has a large density of nodes and very limited energy resource at every node which leads to improved scalability requirements while limiting the resources. This paper proposes a technique called level-based time synchronization to provide redundant ways for each node to synchronize its clock with the common source, so that it can tolerate partially missing or false synchronization information provided by compromised nodes. The efficacy of this technique is evaluated via simulations.