Unique in the shopping mall: On the reidentifiability of credit card metadata

Large-scale data sets of human behavior have the potential to fundamentally transform the way we fight diseases, design cities, or perform research. Metadata, however, contain sensitive information. Understanding the privacy of these data sets is key to their broad use and, ultimately, their impact....

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Bibliographic Details
Main Authors: Radaelli, L., de Montjoye, Yves-Alexandre, Singh, Vivek Kumar, Pentland, Alex Paul
Other Authors: Massachusetts Institute of Technology. Media Laboratory
Format: Article
Language:en_US
Published: American Association for the Advancement of Science (AAAS) 2015
Online Access:http://hdl.handle.net/1721.1/96321
https://orcid.org/0000-0002-8053-9983
https://orcid.org/0000-0001-9086-589X
Description
Summary:Large-scale data sets of human behavior have the potential to fundamentally transform the way we fight diseases, design cities, or perform research. Metadata, however, contain sensitive information. Understanding the privacy of these data sets is key to their broad use and, ultimately, their impact. We study 3 months of credit card records for 1.1 million people and show that four spatiotemporal points are enough to uniquely reidentify 90% of individuals. We show that knowing the price of a transaction increases the risk of reidentification by 22%, on average. Finally, we show that even data sets that provide coarse information at any or all of the dimensions provide little anonymity and that women are more reidentifiable than men in credit card metadata.