Privacy-Preserving Lawful Contact Chaining
[Preliminary Report]

Aaron Segal, Joan Feigenbaum
Yale University

Bryan Ford

Workshop on Privacy in the Electronic Society (WPES)
Vienna, Austria, October 24, 2016


How can government agencies acquire actionable, useful information about legitimate targets, while preserving the privacy of innocent parties and holding government agencies accountable? Towards understanding this crucial issue, we present the first privacy-preserving protocol for contact chaining, an operation that law-enforcement and intelligence agencies have used effectively. Our experiments suggest that a three-hop, privacy-preserving graph traversal producing 27,000 ciphertexts can be done in under two minutes.

Paper: PDF

Aaron Segal was supported by a Google Faculty Research Award.

Joan Feigenbaum was supported in part by NSF grants CNS-1407454 and CNS-1409599, DHS grant FA8750-16-2-0034, and William and Flora Hewlett Foundation grant 2016-3834.

Bryan Ford was supported by EPFL, the AXA Research Fund, and DHS grant FA8750-16-2-0034.