Technology Review: How to Share without Spilling the Beans

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How to Share without Spilling the Beans

A new protocol aims to protect privacy while allowing organizations to share valuable information.

Last fall, two of Israel's leading political parties, Likud and Kadima, became embroiled in a dispute when, in a close primary race, it was alleged that some voters had illegally registered to cast their ballots twice. The parties struggled to find a way to resolve the dispute, since neither wanted to turn over its list of members to the other. Finally, the parties agreed to give their lists to the attorney general, who would compare them confidentially.

This sort of problem is increasingly encountered by large organizations, including government agencies and big businesses, says Andrew Yehuda Lindell , an assistant professor of computer science at Israel's Bar-Ilan University and chief cryptographer at Aladdin Knowledge Systems , in Petach Tikva, Israel. He also calls the solution devised by Likud and Kadima "outrageous," adding that handing over party-membership details to the government is "almost the same as revoking vote confidentiality for these citizens."

Lindell is one of a community of researchers studying ways to share this sort of information without exposing private details. Cryptographers have been working on solutions since the 1980s, and as more data is collected about individuals, Lindell says that it becomes increasingly important to find ways to protect data while also allowing it to be compared. Recently, he presented a cryptographic protocol that uses smart cards to solve the problem.

To use Lindell's new protocol, the first party ("Alice" in cryptography speak) would create a key with which both parties could encrypt their data. The key would be stored on a special kind of secure smart card. Alice would then hand over the smart card to the second party in the scenario (known as "Bob"), and both ...

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http://www.technologyreview.com/communications/22238/?a=f

http://www.technologyreview.com/communications/22238/?a=f