Assuring trustworthiness of sensor data for cyber-physical systems

The term cyber-physical system (CPS) refers to the tight conjoining of and coordination between computational and physical resources. A typical Wireless Sensor Network (WSN) that consists of hundreds off-the-shelf cheap sensor nodes is a common application of a CPS. Each sensor node is equipped with a power-efficient micro-controller, a wireless transmitter, and sensory for environmental monitoring. WSNs are used for monitoring critical infrastructures or habitat monitoring as well as used in military scenarios for urgent decision making. A precondition for such a decision support is to assure the trustworthiness of the reported sensor data. Simply securing the hardware is difficult due to existing resource limitations; in particular power consumption and lack of tamper resistance. A WSN, however, consists of several hundreds of sensor nodes. The idea is to use this redundancy, which is an inherent feature of WSN, to assure trustworthiness. Until now, device redundancy has been used for assuring fault tolerance only but not for security purposes. In this paper, we propose to use device redundancy in WSN to detect and isolate malicious nodes, and with this efficiently protect off-the-shelf WSN as well as assure trustworthiness of sensor data.