Day: May 28, 2009

http://www.schneier.com/blog/archives/2009/05/on_the_anonymit.html

May 21, 2009
On the Anonymity of Home/Work Location Pairs

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“On the Anonymity of Home/Work Location Pairs,” by Philippe Golle and Kurt Partridge:

   Many applications benefit from user location data, but location data raises privacy concerns. Anonymization can protect privacy, but identities can sometimes be inferred from supposedly anonymous data. This paper studies a new attack on the anonymity of location data. We show that if the approximate locations of an individual’s home and workplace can both be deduced from a location trace, then the median size of the individual’s anonymity set in the U.S. working population is 1, 21 and 34,980, for locations known at the granularity of a census block, census track and county respectively. The location data of people who live and work in different regions can be re-identified even more easily. Our results show that the threat of re-identification for location data is much greater when the individual’s home and work locations can both be deduced from the data. To preserve anonymity, we offer guidance for obfuscating location traces before they are disclosed.

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Bruce Schneier highlights that “anonymous data” ain’t so anonymous. AND, the Census is going to collect geo tracking data in the next census. Good bye privacy.

Who authorized the gooferment to do more than count?

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