Unique in the Crowd: The privacy bounds of human mobility

[Eugen Leitl]

(full text available on site)

http://www.nature.com/srep/2013/130325/srep01376/full/srep01376.html

Unique in the Crowd: The privacy bounds of human mobility

Yves-Alexandre de Montjoye,	 Cisar A. Hidalgo,	 Michel Verleysen
& Vincent D. Blondel

Scientific Reports 3, Article number: 1376 doi:10.1038/srep01376

Received 01 October 2012 Accepted 04 February 2013 Published 25 March 2013

We study fifteen months of human mobility data for one and a half million
individuals and find that human mobility traces are highly unique. In fact,
in a dataset where the location of an individual is specified hourly, and
with a spatial resolution equal to that given by the carrier's antennas, four
spatio-temporal points are enough to uniquely identify 95% of the
individuals. We coarsen the data spatially and temporally to find a formula
for the uniqueness of human mobility traces given their resolution and the
available outside information. This formula shows that the uniqueness of
mobility traces decays approximately as the 1/10 power of their resolution.
Hence, even coarse datasets provide little anonymity. These findings
represent fundamental constraints to an individual's privacy and have
important implications for the design of frameworks and institutions
dedicated to protect the privacy of individuals.

Subject terms:

Applied mathematicsComputational scienceStatisticsApplied physics