Document Type

Conference Proceeding



Format of Original

10 p.

Publication Date



Institute of Electrical and Electronics Engineers (IEEE)

Source Publication

2009 33rd Annual IEEE International Computer Software and Applications Conference

Source ISSN


Original Item ID

doi: 10.1109/COMPSAC.2009.11


Recent advances in mobile handheld devices have facilitated the ubiquitous availability of location based services. Systems which provide location based services have always been vulnerable to numerous privacy threats. The more we aim at safe usage of location based services, the more we feel the necessity of a secure location privacy system. Most of the existing systems adopt the mechanism of satisfying k-anonymity which means that the exact user remains indistinguishable among k-1 other users. These systems usually propose the usage of a location anonymizer (LA) to achieve k-anonymity. In this paper we show that satisfying k-anonymity is not enough in preserving location privacy violation. Especially in an environment where a group of colluded service providers collaborate with each other, a userpsilas privacy can be compromised. We present a detailed analysis of such attack on privacy and propose a novel and powerful privacy definition called s-proximity. In addition to building a formal definition for s-proximity, we show that it is practical and it can be incorporated efficiently into existing systems to make them secure.


Accepted version. Published as part of the proceedings of the conference, 2009 33rd Annual IEEE International Computer Software and Applications Conference, 2009: 1-10. DOI. © 2009 The Institute of Electrical and Electronics Engineers. Used with permission.

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