Attack-Tolerant Time-Synchronization in Wireless Sensor Networks

Achieving secure time-synchronization in wireless sensor networks (WSNs) is a challenging, but very important problem that has not yet been addressed effectively. This paper proposes an attack-tolerant time-synchronization protocol (ATSP) in which sensor nodes cooperate to safeguard the time- synchronization service against malicious attacks. ATSP exploits the high temporal correlation existing among adjacent nodes in a WSN to achieve (1) adaptive management of the profile of each sensor´s normal behavior, (2) distributed, cooperative detection of falsified clock values advertised by attackers or compromised nodes, and (3) significant improvement of synchronization accuracy and stability by effectively compensating the clock drifts with the calibrated clock. To reduce the risk of losing time-synchronization due to attacks on the reference node, ATSP utilizes distributed, mutual synchronization and confines the impact of attacks to a local area (where attacks took place). Furthermore, by maintaining an accurate profile of sensors´ normal synchronization behaviors, ATSP detects various critical attacks while incurring only reasonable communication and computation overheads, making ATSP attack-tolerant and ideal for resource-constrained WSNs.