A Flexible Privacy-Enhanced Location-Based Services System Framework and Practice
Location-based services (LBSs) are becoming increasingly important to the success and attractiveness of next-generation wireless systems. However, a natural tension arises between the need for user privacy and the flexible use of location information. In this paper, we present a framework to support privacy-enhanced LBSs. We classify the services according to several basic criteria, and we propose a hierarchical key distribution method to support these services. The main idea behind the system is to hierarchically encrypt location information under different keys, and distribute the appropriate keys only to group members with the necessary permission. Four methods are proposed to deliver hierarchical location information while maintaining privacy. We propose a key tree rebalancing algorithm to maintain the rekeying performance of the group key management. Furthermore, we present a practical LBS system implementation. Hierarchical location information coding offers flexible location information access which enables a rich set of LBSs. Our load tests show such a system is highly practical with good efficiency and scalability.
location-based services hierarchical key distribution location privacy social networks