Preserving location privacy in wireless LANs

The broadcast and tetherless nature of wireless networks and the widespread deployment of Wi-Fi hotspots makes it easy to remotely locate a user by observing her wireless signals. Location is private information and can be used by malicious individuals for blackmail, stalking, and other privacy violations. In this paper, we analyze the problem of location privacy in wireless networks and present a protocol for improving location privacy. Our basic approach is to obfuscate several types of privacy-compromising information revealed by a mobile node, including sender identity, time of transmission, and signal strength. Our design is driven by real-system implementation and field experiments along with analysis and simulations. Our system allows users to choose the level of privacy they desire, thereby increasing the performance of less private users (while not sacrificing private users' privacy at the same time). We evaluated our system based on real-life mobility data and wireless LAN coverage. Our results show that a user of our system can be indistinguishable from a thousand users in the same coverage area.