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Refereed Papers

Track: Mobility

Paper Title:
Supporting Anonymous Location Queries in Mobile Environments with PrivacyGrid


This paper presents PrivacyGrid − a framework for sup- porting anonymous location-based queries in mobile infor- mation delivery systems. The PrivacyGrid framework of- fers three unique capabilities. First, it provides a location privacy protection preference profile model, called location P3P, which allows mobile users to explicitly define their pre- ferred location privacy requirements in terms of both loca- tion hiding measures (e.g., location k-anonymity and loca- tion l-diversity) and location service quality measures (e.g., maximum spatial resolution and maximum temporal resolu- tion). Second, it provides fast and effective location cloaking algorithms for location k-anonymity and location l-diversity in a mobile environment. We develop dynamic bottom- up and top-down grid cloaking algorithms with the goal of achieving high anonymization success rate and efficiency in terms of both time complexity and maintenance cost. A hybrid approach that carefully combines the strengths of both bottom-up and top-down cloaking approaches to fur- ther reduce the average anonymization time is also devel- oped. Last but not the least, PrivacyGrid incorporates temporal cloaking into the location cloaking process to fur- ther increase the success rate of location anonymization. We also discuss PrivacyGrid mechanisms for supporting anonymous location queries. Experimental evaluation shows that the PrivacyGrid approach can provide close to op- timal location k-anonymity as defined by per user location P3P without introducing significant performance penalties.

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