The growing popularity of location-based systems, allowing unknown/untrusted servers to easily collect huge amounts of information regarding users' location, has recently started raising serious privacy concerns. In this paper we introduce geo-indistinguishability, a formal notion of privacy for location-based systems that protects the user's exact location, while allowing approximate information -typically needed to obtain a certain desired service -to be released. This privacy definition formalizes the intuitive notion of protecting the user's location within a radius r with a level of privacy that depends on r, and corresponds to a generalized version of the wellknown concept of differential privacy. Furthermore, we present a mechanism for achieving geo-indistinguishability by adding controlled random noise to the user's location. We describe how to use our mechanism to enhance LBS applications with geo-indistinguishability guarantees without compromising the quality of the application results. Finally, we compare state-of-the-art mechanisms from the literature with ours. It turns out that, among all mechanisms independent of the prior, our mechanism offers the best privacy guarantees.
Andres et al. REF propose geo-indistinguishability, a location privacy model that uses differential privacy to hide a user's exact location in a circle of radius r from locaction based service providers.
Geo-indistinguishability: differential privacy for location-based systems
CCS '13
Computer Science