Handling user-defined private contexts for location privacy in LBS

e present a privacy-preserving framework for the protection of location from potentially untrustworthy location providers (LP), oering geolocation services to LBS subscribers, across indoor and outdoor settings. This framework, called Placeprint, is built on the metaphor of private place[1]. A private place is a user-de ned spatial context which belongs to the personal sphere of an individual, e.g. home. In Placeprint, users equipped with commodity devices, can be geolocated in private places without revealing to the LP their presence. Moreover users can specify context-based privacy rules to forestall the disclosure of private places also to LBS providers. The ultimate goal is to provide users with the capability of exercising exible control over the disclosure of the position to both LP and LBS provider.