Hide & Crypt: Protecting Privacy in Proximity-Based Services

A particular class of location based services, called friend finder , is becoming very popular. Using this kind of service, a subscriber obtains to know location information about other participants (called buddies). Current commercial applications of this service imply the acquisition by the service provider of the user location at the best possible precision. This can discourage many users to use this service, since the precise location is a private information. We present a privacy-aware friend finder system called Hide&Crypt that notifies a user whether her buddies are within a user-specified threshold distance. The user can specify her location privacy requirements both with respect to the service provider and to the other buddies. The system includes a server application, and clients for mobile devices and desktop computers.