A Scheme for Secure and Reliable Distributed Data Storage in Unattended WSNs

Unattended Wireless Sensor Networks (UWSNs) operated in hostile environments face a risk on data security due to the absence of real-time communication between sensors and sinks, which imposes sensors to accumulate data till the next visit of a mobile sink to off-load the data. Thus, how to ensure forward secrecy, backward secrecy and reliability of the accumulated data is a great challenge. For example, if a sensor is compromised, pre-compromise data accumulated in the sensor is exposed to access. In addition, by holding key secrecy of the compromised sensor, attackers also can learn post-compromise data in the sensor. Furthermore, in practical UWSNs, once sensors stop working for accidents due to node crash or battery depletion, all the data accumulated will be lost. To address the challenges, we propose a secure and reliable data distribution scheme in this paper. Detailed analysis shows that our scheme can provide forward secrecy, probabilistic backward secrecy and data reliability. To further improve probabilistic backward secrecy and data reliability, a constrained optimization data distribution scheme is proposed. Detailed analysis and simulation results show the superiority of the proposed scheme in comparison with several previous approaches developed for UWSNs.