Providing Privacy in Location Based Services

In the last years, the availability of cheap mobile devices able to communicate via radio interfaces and equipped with low cost positioning technologies, like GPS, has brought to researcher attention a new kind of services: location based services (LBS). LBS require users to provide their position in order to customize the service. This, of course, could be a threat for user privacy by at least two points of view. First of all, when a user performs a query to the LBS provider, she may disclose sensitive data. Imagine a user looking for a vegetarian restaurant: the LBS provider becomes aware that the issuer is vegetarian. Moreover, each query discloses user position, so the provider can track user location. In this paper, we analyze existing approaches that address privacy issues in LBS, identifying their effectiveness on the basis of the knowledge contexts available to a potential attacker. A novel architectural framework is provided to analyze and classify proposed solutions on the basis of their connectivity and architectural requirements.