  We present a new class of statistical de-anonymization attacks against
high-dimensional micro-data, such as individual preferences, recommendations,
transaction records and so on. Our techniques are robust to perturbation in the
data and tolerate some mistakes in the adversary's background knowledge.
  We apply our de-anonymization methodology to the Netflix Prize dataset, which
contains anonymous movie ratings of 500,000 subscribers of Netflix, the world's
largest online movie rental service. We demonstrate that an adversary who knows
only a little bit about an individual subscriber can easily identify this
subscriber's record in the dataset. Using the Internet Movie Database as the
source of background knowledge, we successfully identified the Netflix records
of known users, uncovering their apparent political preferences and other
potentially sensitive information.
