Location-based services are becoming an important part of our everyday lives. According to the Pew Internet & American Life Project survey, 47% of current cell-phone users prefer to have mapping features on their phones. Similar trends can be shown for other portable devices such as car navigation systems, PDA's and computer laptops. However, recent concerns over how such services can jeopardize a user's private information resulted in the newly coined term "location privacy." Several breaches of subscriber's privacy by stalking their locations have been reported. This project is going beyond the conventional approaches proposed for location privacy by devising novel frameworks to eliminate the need for a trusted intermediary (acting as an anonymizer) in location-based services and that satisfy significantly more stringent privacy guarantees as compared to the anonymity-based approaches. The first approach is inspired by the work in the area of encryption and the second approach builds upon the framework of private information retrieval. Both of these research fields have been around for a long time enabling privacy protection but not yet fully exploited for location privacy. The broader impact of this study is to enable many users with privacy concerns to utilize customized location services in their mobile devices without compromising their location privacy. This in turn would increase the customer base for many industries and government agencies in the areas of geospatial information systems, online maps, car navigation systems, Location Based Services, and military and intelligence operations. Results will be disseminated through papers published in relevant conferences and journals; open-source code will be disseminated through the web: http://infolab.usc.edu/projects/LocationPrivacy/.
