[Infowarrior] - Anonymity of Home/Work Location Pairs

[Richard Forno]

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

Abstract:
Philippe Golle and Kurt Partridge of PARC

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.

http://crypto.stanford.edu/~pgolle/papers/commute.pdf