Whither data privacy?
On Friday Netflix canceled the sequel to its Netflix prize due to privacy concerns. The announcement of the cancellation has had a mixed reception from both researchers and the public. Narayanan and Shmatikov, the researchers who exposed the privacy issues in the original Netflix prize competition data, write “Today is a sad day. It is also a day of hope.”
The Netflix prize data example is probably the third most famous example of de-anonymization of data that was released with the explicit claim that the data had been anonymized. These examples differ from the privacy breaches discussed by Maribeth Back in her post on ChatRoulette or the issues with Google Buzz discussed as part of Gene Golovchinsky’s post “What’s private on the Web?” . Those examples made sensitive information available directly. In the case of the following three de-anonymization attacks, the data itself was “anonymized,” but researchers were able, with the addition of publicly available auxiliary information, de-anonymize much of the data.