Testbed Implementation of a Secure Flooding Time Synchronization Protocol

A fundamental building block in distributed wireless sensor networks is time synchronization. Given resource constrained nature of sensor networks, previous research has focused on developing various energy efficient time synchronization protocols tailored for these networks. However, many of these protocols have not been designed with security in mind. In this paper, we describe FTSP which is one of the major time synchronization protocols for sensor networks. We outline the adverse effects of the time synchronization attacks on some important sensor network applications, and explain the set of possible attacks on FTSP. We then propose a number of countermeasures to mitigate the effect of the security attacks. We implement these attack scenarios on a sensor network testbed and show the extent each attack is successful in desynchronizing the network. Finally, we implement the countermeasures on our sensor network testbed to validate their usefulness in mitigating security attacks. We show that adding a sequence number filter to the original FTSP helps mitigate the effect of attacks on this protocol.