Self-healing in unattended wireless sensor networks, ACM Transaction on Sensor Networks 9 (1) (2012). Article 7.Please cite this article in press as

Wireless Sensor Networks (WSNs) appeal to a wide range of applications that involve monitoring of various physical phe-nomena. However, WSNs are subject to many threats. In particular, lack of pervasive tamper-resistant hardware results in sensors being easy targets for compromise. Having compromised a sensor, the adversary learns all the sensor secrets, allow-ing it to later encrypt/decrypt or authenticate messages on behalf of that sensor. This threat is particularly relevant in the novel Unattended Wireless Sensor Networks (UWSNs) scenario. UWSNs operate without constant supervision by a trusted sink. UWSN’s unattended nature and increased exposure to attacks prompts the need for special techniques geared towards regaining security after compromise. In this paper we investigate cooperative self-healing in UWSNs and propose various techniques to allow unattended sensors to recover security after compromise. Our techniques provide seamless healing rates even against a very agile and powerful adversary. The effectiveness and viability of proposed techniques is assessed by thorough analysis and supported by simulation results. Finally, we introduce some real world issues affecting UWSN deployment, and provide some solutions to them as well as a few open problems calling for further investigation