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BACTAC - Gruteser

Privacy for Location-Based Services Through Automatic Resolution Control
Graduate Student, Department of Computer Science

Location-based services promise to provide users with information about their surroundings or help them to navigate unknown areas, for example. However, they also cause immense privacy concerns, because they typically require that users transmit their current position to an external service provider.

We propose location privacy mechanisms using automatic resolution control, which require less user attention and configuration than privacy policy-based approaches. Position information collected from GPS or wireless LAN can be so precise that, even if the user issues a query without explicit user identification, an adversary could learn the user's identity by linking the position to publicly available, identified location records. Choosing an unnecessarily low resolution can severely degrade the service quality, thus automatic resolution control reveals position information at the highest resolution that still preserves anonymity.

We developed a Linux-based prototype that adjusts resolution by monitoring the density of wireless LAN users. The prototype also changes the network interface identifier, so that a user's movements between different network access points cannot be tracked.

Department of Computer Science
University of Colorado Boulder
Boulder, CO 80309-0430 USA
May 5, 2012 (14:24)