On the Use of Fake Sources for Source Location Privacy: Trade-Offs Between Energy and Privacy

Wireless sensor networks have enabled novel applications such as monitoring, where security is invariably a requirement. One aspect of security, namely source location privacy, is becoming an increasingly important property of some wireless sensor network applications. The fake source technique has been proposed as an efficient technique to handle the source location privacy problem. However, there are several factors that limit the usefulness of current results: (i) the selection of fake sources is dependent on sophisticated nodes, (ii) fake sources are known a priori and (iii) the selection of fake sources is based on a prohibitively expensive pre-configuration phase. In this paper, we investigate the privacy enhancement and energy efficiency of different implementations of the fake source technique that circumvents these limitations. Our results show that the fake source technique is indeed effective in enhancing privacy. Specifically, one implementation achieves near-perfect privacy when there is at least one fake source in the network, at the expense of increased energy consumption. In the presence of multiple attackers, the same implementation yields only a 30% decrease in capture ratio with respect to flooding. To address this problem, we propose a hybrid technique which achieves a corresponding 50% reduction in the capture ratio and a near-perfect privacy whenever at least one fake source exists in the network.