Cryptographic Spatio-temporal Predicates for Location-Based Services

The increasing spread of location-based services (LBSs) has led to a renewed research interest in location-based security, especially location-based access control. It also raises a lot of concern on potential privacy violation due to the possibility of identifying the user who requests a given service based on her/his location information at the time of the request. To ensure the credibility and availability of LBSs, there is a pressing requirement for addressing security and privacy issues of LBSs in a synergistic way. In this paper, we propose an innovative access control mechanism for LBSs, enabling both fine-grained access control and effective privacy protection. Our proposed approach is based on the construction of cryptographic spatio-temporal predicates by means of efficient secure integer comparison. Our experimental results not only validate the effectiveness of our scheme, but also demonstrate that the proposed integer comparison scheme performs better than previous bit wise comparison scheme.