22 Privacy - enhanced Location - based Access Control

Advancements in location technologies reliability and precision are fostering the development of location-based services that make use of the location information of users. An increasingly important category of such services is represented by Location-based Access Control (LBAC) systems that integrate traditional access control mechanisms with access conditions based on the physical position of users and other attributes related to the users location. Since privacy is extremely important for users, protection of their location information is paramount to the success of such emerging location-based services. In this chapter, we first present an overview of Location-based Access Control systems and then characterize the location privacy protection problem. We then discuss the main techniques that have been proposed to protect location information, focusing on the obfuscation-based techniques. We conclude the chapter by showing a privacy-aware LBAC architecture and describing how a location-based access control policy can be evaluated.