Track me if you can: Transparent obfuscation for Location based Services

Although Location-based Services (LBSs) offer evident advantages to their users, many privacy concerns are sought when user tracking data are shared with the service provider. Existing privacy enhancing solutions (e.g. k-anonymity) usually degrade service precision, and also require the collaboration of the service provider-this latter one not always willing to lose control over the user´s location data. In this paper, we propose a solution that is able to obfuscate the user´s path to the service provider, while preserving (for the LBS) the capability to compute a few functions-useful for the user-over the obfuscated path. In particular, we provide several contributions: first, we formalize the concept of obfuscation function, and we propose a solution that provides user privacy while allowing users to continue leveraging the services offered by the service provider. Moreover, we formally prove the privacy preserving properties of our approach. Finally, an extensive experimental campaign supports the feasibility of our approach, showing that the proposed solution can be efficiently implemented over mobile device.