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BACTAC - Gruteser

Anonymous Usage of Location-Based Services Through Spatial and Temporal Cloaking
Graduate Student, Department of Computer Science

Advances in sensing and tracking technology enable location-based applications but they also create significant privacy risks. Anonymity can provide a high degree of privacy, saves service users from dealing with service providers' privacy policies, and reduces the service providers' requirements for safeguarding private information. However, guaranteeing anonymous usage of location-based services requires that the precise location information transmitted by a user can not be easily used to re-identify the subject. This paper presents a middleware architecture and algorithms that can be used by a centralized location broker service. The adaptive algorithms adjust the resolution of location information along spatial or temporal dimensions to meet specified anonymity constraints based on the entities who may be using location services within a given area. Using a model based on automotive traffic counts and cartographic material, we estimate the realistically expected spatial resolution for different anonymity constraints. The median resolution generated by our algorithms is 125 meters. This means that anonymous location-based queries for urban areas would have the same accuracy currently needed for E-911 services, and would provide sufficient resolution for wayfinding, automated bus routing services and similar location-dependent services.

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