PROBE: An Obfuscation System for the Protection of Sensitive Location Information in LBS

The widespread adoption of location-based services (LBS) raises increasing concerns for the protection of personal location information. A common strategy, referred to as obfuscation, to protect location privacy is based on forwarding the LSB provider a coarse user location instead of the actual user location. Conventional approaches, based on such technique, are however based only on geometric methods and therefore are unable to assure privacy when the adversary has semantic knowledge about the reference spatial context. This paper provides a comprehensive solution to this problem. Our solution presents a novel approach that obfuscates the user location by taking into account the semantic knowledge about the reference space. In the paper, we de ne several theoretical notions underlying our approach. We then propose two different strategies for generating obfuscated spaces. The paper also includes several experimental results assessing performance, storage requirements and accuracy for the two approaches. The paper also discusses the system architecture and shows that the approach can be deployed also for clients running on small devices