Hidden Anchor: Providing Physical Layer Location Privacy in Hybrid Wireless Sensor Networks

In many hybrid wireless sensor networks (HWSNs) applications, sensor nodes are deployed in hostile environments where trusted and un-trusted nodes co-exist. In such hybrid networks, it becomes important to allow trusted nodes to share information, especially, location information and, at the same time, prevent un-trusted nodes from gaining access to this information. We focus on anchor-based localization algorithms in HWSNs, where a small set of specialized nodes, i.e. anchor nodes, broadcast their location to the network and other nodes can use the broadcast information to estimate their own location. The main challenge is that both trusted and un-trusted nodes can measure the physical signal transmitted from anchor nodes. Thus, un-trusted nodes can use the physical signal transmitted from an anchor node to estimate its location. In this paper, we propose hidden anchor, an algorithm that provides anchor physical layer location privacy. The hidden anchor algorithm exploits the inherently noisy wireless channel and uses identity cloning of neighboring trusted nodes to make anchors unobservable to untrusted nodes while providing complete information to trusted nodes. Evaluation of the hidden anchor algorithm through analysis and simulation shows that it can hide the location and identity of anchor nodes with very low overhead.