iGPS: Privacy-Preserving Geo-Proximity Services in Location-based Social Networks
Project Team: Prof. XU, Jian Liang
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Abstract |
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A geo-proximity service in location-based social networks alerts a mobile user when any of his/her friends is in the geographical vicinity, so as to enrich social activities such as collaborative working and information sharing. To realize such services, existing systems collect location information from mobile users for proximity computation, which raises serious privacy concerns. This project aims to develop more sophisticated location update and query techniques that support these geo-proximity services while preserving the location privacy of mobile users.
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Case Study |
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You are walking downtown and would like to invite a friend nearby for lunch. Our "Nearby Friedy Alert" app can pop up nearby friends without having these friends disclosing their locations to the server or you.
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Methodology |
- "Grid and hashing"
The basic idea of proximity detection without disclosing user locations is to apply a one-way space transformation (i.e., "grid-and-hashing") that preserves proximity, and the server then detects proximity in the transformed space.
- Grid overlay
However, this comes at a price of "false-negative" cases - that is, two users are detected as "not in-proximity" while they actually are. To overcome this issue, we impose more than one grid partition G1, ..., Gn. The overlaid grids significantly reduce the probability that two close users are separated by all grid partitions.
- Grid Hierarchy and Dynamic Update
To reduce the cost of user moving and location update, we design a multi-level grid hierarchy, so that updates for farther-away pairs are restrained in upper level and thus less frequent.
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Publication |
- H. Li, H. Hu, J. Xu. "Nearby Friend Alert: Location Anonymity in Mobile Geo-Social Networks". IEEE Pervasive Computing, accepted to appear, 2012.
- X. Lin, H. Hu, H. P. Li, J. Xu, and B. Choi. "Private Proximity Detection and Monitoring with Vicinity Regions." Proceedings of 12th International ACM SIGMOD Workshop on Data Engineering for Wireless and Mobile Access (MobiDE '13), New York, New York, June 2013.
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Patent Application |
- J. Xu and H. Hu. "A System and Method for Providing Proximity Information." US Non-Provisional Patent Application No. 13/905,456.
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For further information on this project, please contact Prof. XU, Jian Liang.
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