Making Privacy-Preserving Data Mining Practical with Smartcards∗

Data mining provides large benefits to the commercial, government and homeland security sectors, but the aggregation and storage of huge amounts of data about citizens inevitably leads to an erosion of privacy. To achieve the benefits that data mining has to offer, while at the same time enhancing privacy, we need technological solutions that simultaneously enable data mining while preserving privacy. This need has been recognized by the US government, as can be seen in the February 2008 report on data mining by the Office of the Director of National Intelligence (see pages 9-12). In this paper, we present surprisingly simple and extraordinarily efficient protocols for a number of non-trivial tasks related to privacy-preserving data mining. Our protocols use standard smartcards and standard smartcard infrastructure, and are the first truly practical solutions for these problems that provide strong security guarantees.