{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,8]],"date-time":"2026-01-08T02:32:16Z","timestamp":1767839536717,"version":"3.49.0"},"reference-count":55,"publisher":"Association for Computing Machinery (ACM)","issue":"4","license":[{"start":{"date-parts":[[2018,2,3]],"date-time":"2018-02-03T00:00:00Z","timestamp":1517616000000},"content-version":"vor","delay-in-days":365,"URL":"http:\/\/www.acm.org\/publications\/policies\/copyright_policy#Background"}],"funder":[{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["CNS-13-18415"],"award-info":[{"award-number":["CNS-13-18415"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["dl.acm.org"],"crossmark-restriction":true},"short-container-title":["ACM Trans. Priv. Secur."],"published-print":{"date-parts":[[2017,2,3]]},"abstract":"<jats:p>Location-based services have become an integral part of everyday life. To address the privacy issues that emerge from the use and sharing of location information, social networks and smartphone applications have adopted location proximity schemes as a means of balancing user privacy with utility. Unfortunately, despite the extensive academic literature on this topic, the schemes that large service providers have adopted are not always designed or implemented correctly, rendering users vulnerable to location-disclosure attacks. Such attacks have recently received major publicity as, in some cases, they even exposed citizens of oppressive regimes to life-threatening risks. In this article, we systematically assess the defenses that popular location-based services and mobile applications deploy to guard against adversaries seeking to identify a user\u2019s location. We provide the theoretical foundations for formalizing the privacy guarantees of currently adopted proximity models, design practical attacks for each case, and prove tight bounds on the number of queries required for carrying out successful attacks in practice.<\/jats:p>\n                  <jats:p>To evaluate the completeness of our approach, we conduct extensive experiments against popular services including Facebook, Foursquare, and Grindr. Our results demonstrate that, even though the aforementioned services implement various privacy-preserving techniques to protect their users, they are still vulnerable to attacks. In particular, we are able to pinpoint Facebook users within 5m of their exact location. For Foursquare and Grindr, users are pinpointed within 15m of their location in 90% of the cases, even with the strictest privacy settings enabled. Our attacks are highly efficient and complete within a few seconds. The severity of our findings was acknowledged by Facebook and Foursquare, both of which have followed our recommendations and adopted our design of a safe proximity scheme in their production systems. As the number of mobile applications offering location functionality will continue to increase, service providers and software developers must be able to assess the privacy guarantees that their services offer. To that end, we discuss viable defenses that can be currently adopted by all major services, and provide an open-source testing framework to be used by researchers and service providers who wish to evaluate the privacy-preserving properties of applications offering proximity functionality.<\/jats:p>","DOI":"10.1145\/3007209","type":"journal-article","created":{"date-parts":[[2017,2,10]],"date-time":"2017-02-10T08:28:54Z","timestamp":1486715334000},"page":"1-31","update-policy":"https:\/\/doi.org\/10.1145\/crossmark-policy","source":"Crossref","is-referenced-by-count":15,"title":["Evaluating the Privacy Guarantees of Location Proximity Services"],"prefix":"10.1145","volume":"19","author":[{"given":"George","family":"Argyros","sequence":"first","affiliation":[{"name":"Network Security Lab, Columbia University, New York, NY"}]},{"given":"Theofilos","family":"Petsios","sequence":"additional","affiliation":[{"name":"Network Security Lab, Columbia University, New York, NY"}]},{"given":"Suphannee","family":"Sivakorn","sequence":"additional","affiliation":[{"name":"Network Security Lab, Columbia University, New York, NY"}]},{"given":"Angelos D.","family":"Keromytis","sequence":"additional","affiliation":[{"name":"Network Security Lab, Columbia University, New York, NY"}]},{"given":"Jason","family":"Polakis","sequence":"additional","affiliation":[{"name":"Computer Science Department, University of Illinois at Chicago, Chicago, IL"}]}],"member":"320","published-online":{"date-parts":[[2017,2,3]]},"reference":[{"key":"e_1_2_1_1_1","doi-asserted-by":"publisher","DOI":"10.1145\/2508859.2516735"},{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","unstructured":"Leyla Bilge Thorsten Strufe Davide Balzarotti and Engin Kirda. 2009. All your contacts belong to us: Automated identity theft attacks on social networks. In ACM WWW\u201909. 10.1145\/1526709.1526784","DOI":"10.1145\/1526709.1526784"},{"key":"e_1_2_1_3_1","doi-asserted-by":"publisher","DOI":"10.1145\/2660267.2660345"},{"key":"e_1_2_1_4_1","doi-asserted-by":"publisher","DOI":"10.5555\/993483"},{"key":"e_1_2_1_5_1","unstructured":"A. Chaabane G. Acs and M. A. Kaafar. 2012. You are what you like&excl; Information leakage through users\u2019 interests. In NDSS\u201912."},{"key":"e_1_2_1_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/0012-365X(90)90358-O"},{"key":"e_1_2_1_7_1","volume-title":"Retrieved","author":"Constine Josh","year":"2014","unstructured":"Josh Constine. 2014a. Techcrunch - Ambient Proximity Is The Next Phase Of Location Sharing. Retrieved November 28, 2016 from http:\/\/techcrunch.com\/2014\/05\/01\/ambient-proximity."},{"key":"e_1_2_1_8_1","volume-title":"Techcrunch - Facebook Launches Nearby Friends With Opt-In Real-Time Location Sharing To Help You Meet Up. Retrieved","author":"Constine Josh","year":"2014","unstructured":"Josh Constine. 2014b. Techcrunch - Facebook Launches Nearby Friends With Opt-In Real-Time Location Sharing To Help You Meet Up. Retrieved November 28, 2016 from http:\/\/techcrunch.com\/2014\/04\/17\/facebook-nearby-friends."},{"key":"e_1_2_1_9_1","doi-asserted-by":"publisher","DOI":"10.5555\/580470"},{"key":"e_1_2_1_10_1","volume-title":"Nandy","author":"De Minati","year":"2011","unstructured":"Minati De, Gautam K. Das, and Subhas C. Nandy. 2011. Approximation algorithms for the discrete piercing set problem for unit disks. In CCCG."},{"key":"e_1_2_1_11_1","volume-title":"Wireless E911 location accuracy requirements. Ps Docket 07-114","author":"Federal Communications Commission","year":"2015","unstructured":"Federal Communications Commission. 2015. Wireless E911 location accuracy requirements. Ps Docket 07-114 (2015)."},{"key":"e_1_2_1_12_1","doi-asserted-by":"publisher","DOI":"10.1145\/2660267.2662389"},{"key":"e_1_2_1_13_1","unstructured":"D. Foo Kune J. Koelndorfer N. Hopper and Y. Kim. 2012. Location leaks on the GSM air interface (NDSS\u201912)."},{"key":"e_1_2_1_14_1","volume-title":"Retrieved","author":"Forum Police","year":"2013","unstructured":"Police Forum. 2013. Police Forum - Social Media and Tactical Considerations For Law Enforcement. Retrieved November 28, 2016 from http:\/\/www.policeforum.org\/assets\/docs\/Free_Online_Documents\/Technology\/social%20media%20and%20tactical%20considerations%20for%20law%20enforcement%202013.pdf."},{"key":"e_1_2_1_15_1","volume-title":"Locations. Retrieved","author":"Frizell Sam","year":"2014","unstructured":"Sam Frizell. 2014. Time - Tinder Security Flaw Exposed Users\u2019 Locations. Retrieved November 28, 2016 from http:\/\/time.com\/8604\/tinder-app-user-location-security-flaw\/."},{"key":"e_1_2_1_16_1","doi-asserted-by":"publisher","DOI":"10.1145\/1653771.1653807"},{"key":"e_1_2_1_17_1","volume-title":"Retrieved","author":"Greenwald Glenn","year":"2013","unstructured":"Glenn Greenwald and Ewen MacAskill. 2013. The Guardian - NSA Prism program taps in to user data of Apple, Google and others. Retrieved November 28, 2016 from http:\/\/www.guardian.co.uk\/world\/2013\/jun\/06\/us-tech-giants-nsa-data."},{"key":"e_1_2_1_18_1","volume-title":"Retrieved","year":"2014","unstructured":"Grindr. 2014. Grindr - Location Security Update. Retrieved November 28, 2016 from http:\/\/grindr.com\/blog\/grindrs-location-security-update\/."},{"key":"e_1_2_1_19_1","doi-asserted-by":"publisher","unstructured":"Marco Gruteser and Dirk Grunwald. 2003. Anonymous usage of location-based services through spatial and temporal cloaking. In MobiSys. 10.1145\/1066116.1189037","DOI":"10.1145\/1066116.1189037"},{"key":"e_1_2_1_20_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.is.2012.07.001"},{"key":"e_1_2_1_21_1","volume-title":"The Elements of Statistical Learning","author":"Hastie Trevor","unstructured":"Trevor Hastie, Robert Tibshirani, and Jerome Friedman. 2001. The Elements of Statistical Learning. Springer, New York, NY."},{"key":"e_1_2_1_22_1","doi-asserted-by":"publisher","DOI":"10.1080\/03772063.2014.890826"},{"key":"e_1_2_1_23_1","unstructured":"Yaoqi Jia Xinshu Dong Zhenkai Liang and Prateek Saxena. 2014. I know where you\u2019ve been: Geo-inference attacks via the browser cache. In W2SP\u201914."},{"key":"e_1_2_1_24_1","volume-title":"Retrieved","author":"Lardner Richard","year":"2010","unstructured":"Richard Lardner. 2010. Huffington Post - Feds Using Fake Online Profiles To Spy On Suspects. Retrieved November 28, 2016 from http:\/\/www.huffingtonpost.com\/2010\/03\/16\/fbi-uses-fake-facebook-pr_n_500776.html."},{"key":"e_1_2_1_25_1","doi-asserted-by":"publisher","DOI":"10.1109\/MPRV.2012.82"},{"key":"e_1_2_1_26_1","doi-asserted-by":"publisher","unstructured":"Muyuan Li Haojin Zhu Zhaoyu Gao Si Chen Le Yu Shangqian Hu and Kui Ren. 2014. All your locations belong to us: Breaking mobile social networks for automated user location tracking. In MobiHoc. 10.1145\/2632951.2632953","DOI":"10.1145\/2632951.2632953"},{"key":"e_1_2_1_27_1","volume-title":"Denis Foo Kune, and Nicholas Hopper","author":"Lin Zi","year":"2012","unstructured":"Zi Lin, Denis Foo Kune, and Nicholas Hopper. 2012. Efficient private proximity testing with GSM location sketches. In Financial Cryptography and Data Security."},{"key":"e_1_2_1_28_1","doi-asserted-by":"crossref","unstructured":"M. V. Marathe H. Breu H. B. Hunt III S. S. Ravi and D. J. Rosenkrantz. 1995. Simple heuristics for unit disk graphs. NETWORKS 25.","DOI":"10.1002\/net.3230250205"},{"key":"e_1_2_1_29_1","doi-asserted-by":"crossref","unstructured":"Claudio Marforio Nikolaos Karapanos Claudio Soriente Kari Kostiainen and Srdjan Capkun. 2014. Smartphones as practical and secure location verification tokens for payments (NDSS\u201914).","DOI":"10.14722\/ndss.2014.23165"},{"key":"e_1_2_1_30_1","doi-asserted-by":"publisher","DOI":"10.1137\/0111030"},{"key":"e_1_2_1_31_1","doi-asserted-by":"publisher","DOI":"10.1109\/MDM.2013.19"},{"key":"e_1_2_1_32_1","doi-asserted-by":"publisher","DOI":"10.1109\/MDM.2009.14"},{"key":"e_1_2_1_33_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00778-010-0213-7"},{"key":"e_1_2_1_34_1","unstructured":"Shigeru Masuyama Toshihide Ibaraki and Toshiharu Hasegawa. 1981. Computational complexity of the m-center problems on the plane. IEICE Transactions E64 2 57--64."},{"key":"e_1_2_1_35_1","doi-asserted-by":"publisher","unstructured":"Kazuhiro Minami and Nikita Borisov. 2010. Protecting location privacy against inference attacks (WPES\u201910). 10.1145\/1866919.1866938","DOI":"10.1145\/1866919.1866938"},{"key":"e_1_2_1_36_1","unstructured":"Arvind Narayanan Narendran Thiagarajan Michael Hamburg Mugdha Lakhani and Dan Boneh. 2011. Location privacy via private proximity testing. In NDSS\u201911."},{"key":"e_1_2_1_37_1","doi-asserted-by":"publisher","unstructured":"Tim Nieberg and Johann Hurink. 2006. A PTAS for the minimum dominating set problem in unit disk graphs. In WAOA. 10.1007\/11671411_23","DOI":"10.1007\/11671411_23"},{"key":"e_1_2_1_38_1","volume-title":"RetrievedNovember 28","author":"Noack Rick","year":"2014","unstructured":"Rick Noack. 2014. Washington Post - Could using gay dating app Grindr get you arrested in Egypt? RetrievedNovember 28, 2016 from http:\/\/www.washingtonpost.com\/blogs\/worldviews\/wp\/2014\/09\/12\/could-using-gay-dating-app-grindr-get-you-arrested-in-egypt\/."},{"key":"e_1_2_1_39_1","volume-title":"Retrieved","author":"Paton Callum","year":"2014","unstructured":"Callum Paton. 2014. The Independent - Grindr and Egypt. Retrieved November 28, 2016 from http:\/\/www.independent.co.uk\/news\/world\/africa\/9757652.html."},{"key":"e_1_2_1_40_1","doi-asserted-by":"publisher","DOI":"10.1145\/2523649.2523653"},{"key":"e_1_2_1_41_1","doi-asserted-by":"publisher","DOI":"10.1145\/1734583.1734585"},{"key":"e_1_2_1_42_1","unstructured":"Guojun Qin Constantinos Patsakis and M\u00e9lanie Bouroche. 2014. Playing hide and seek with mobile dating applications. In IFIP SEC\u201914."},{"key":"e_1_2_1_43_1","volume-title":"Retrieved","author":"Scheck Justin","year":"2010","unstructured":"Justin Scheck. 2010. WSJ - Stalkers Exploit Cellphone GPS. Retrieved November 28, 2016 from http:\/\/online.wsj.com\/articles\/SB10001424052748703467304575383522318244234."},{"key":"e_1_2_1_44_1","doi-asserted-by":"publisher","DOI":"10.1109\/SP.2011.18"},{"key":"e_1_2_1_45_1","doi-asserted-by":"publisher","unstructured":"Reza Shokri George Theodorakopoulos Carmela Troncoso Jean-Pierre Hubaux and Jean-Yves Le Boudec. 2012. Protecting location privacy: Optimal strategy against localization attacks (CCS\u201912). 10.1145\/2382196.2382261","DOI":"10.1145\/2382196.2382261"},{"key":"e_1_2_1_46_1","doi-asserted-by":"publisher","DOI":"10.1109\/MDM.2010.43"},{"key":"e_1_2_1_47_1","volume-title":"Man Lung Yiu, and Ove Andersen","author":"\u0160ik\u0161nys Laurynas","year":"2009","unstructured":"Laurynas \u0160ik\u0161nys, Jeppe R. Thomsen, Simonas \u0160altenis, Man Lung Yiu, and Ove Andersen. 2009. A location privacy aware friend locator. In SST\u201909."},{"key":"e_1_2_1_48_1","doi-asserted-by":"publisher","unstructured":"George Theodorakopoulos Reza Shokri Carmela Troncoso Jean-Pierre Hubaux and Jean-Yves Le Boudec. 2014. Prolonging the hide-and-seek game: Optimal trajectory privacy for location-based services. In WPES\u201914. 10.1145\/2665943.2665946","DOI":"10.1145\/2665943.2665946"},{"key":"e_1_2_1_49_1","doi-asserted-by":"publisher","unstructured":"Federico Thomas and Llus Ros. 2005. Revisiting trilateration for robot localization. Transactions on Robotics\u201905 21 1. 10.1109\/TRO.2004.833793","DOI":"10.1109\/TRO.2004.833793"},{"key":"e_1_2_1_50_1","doi-asserted-by":"publisher","unstructured":"You-Chiun Wang Chun-Chi Hu and Yu-Chee Tseng. 2005. Efficient deployment algorithms for ensuring coverage and connectivity of wireless sensor networks. In Wireless Internet\u201905. 10.1109\/WICON.2005.13","DOI":"10.1109\/WICON.2005.13"},{"key":"e_1_2_1_51_1","volume-title":"Retrieved","author":"Wardle Patrick","year":"2014","unstructured":"Patrick Wardle. 2014. Synack Security - The Do\u2019s and Don\u2019ts of Location Aware Apps; A Case Study. (2014). Retrieved November 28, 2016 from https:\/\/www.synack.com\/labs\/projects\/the-dos-and-donts-of-location-aware-apps-a-case-study."},{"key":"e_1_2_1_52_1","first-page":"1","article-title":"Human mobility enhances global positioning accuracy for mobile phone localization","volume":"99","author":"Yang Zheng","year":"2014","unstructured":"Zheng Yang, Yiyang Zhao, Yunhao Liu, and Yu Xu. 2014. Human mobility enhances global positioning accuracy for mobile phone localization. IEEE Transactions on Parallel and Distributed Systems 99, 1.","journal-title":"IEEE Transactions on Parallel and Distributed Systems"},{"key":"e_1_2_1_53_1","doi-asserted-by":"crossref","unstructured":"Xinxin Zhao Lingjun Li and Guoliang Xue. 2013. Checking in without worries: Location privacy in location based social networks. In INFOCOM\u201913.","DOI":"10.1109\/INFCOM.2013.6567112"},{"key":"e_1_2_1_54_1","volume-title":"SHARP: Private proximity test and secure handshake with cheat-proof location tags. In ESORICS\u201912.","author":"Zheng Yao","year":"2012","unstructured":"Yao Zheng, Ming Li, Wenjing Lou, and Y. Thomas Hou. 2012. SHARP: Private proximity test and secure handshake with cheat-proof location tags. In ESORICS\u201912."},{"key":"e_1_2_1_55_1","doi-asserted-by":"publisher","unstructured":"Ge Zhong Ian Goldberg and Urs Hengartner. 2007. Louis Lester and Pierre: Three protocols for location privacy. In PETS\u201907.","DOI":"10.5555\/1779330.1779335"}],"container-title":["ACM Transactions on Privacy and Security"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dl.acm.org\/doi\/10.1145\/3007209","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/dl.acm.org\/doi\/pdf\/10.1145\/3007209","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/dl.acm.org\/doi\/pdf\/10.1145\/3007209","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,18]],"date-time":"2025-11-18T09:30:47Z","timestamp":1763458247000},"score":1,"resource":{"primary":{"URL":"https:\/\/dl.acm.org\/doi\/10.1145\/3007209"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,2,3]]},"references-count":55,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2017,2,3]]}},"alternative-id":["10.1145\/3007209"],"URL":"https:\/\/doi.org\/10.1145\/3007209","relation":{},"ISSN":["2471-2566","2471-2574"],"issn-type":[{"value":"2471-2566","type":"print"},{"value":"2471-2574","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,2,3]]},"assertion":[{"value":"2015-12-01","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2016-10-01","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2017-02-03","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}