Cryptology ePrint Archive: Report 2019/634

SpOT-Light: Lightweight Private Set Intersection from Sparse OT Extension

Benny Pinkas and Mike Rosulek and Ni Trieu and Avishay Yanai

Abstract: We describe a novel approach for two-party private set intersection (PSI) with semi-honest security. Compared to existing PSI protocols, ours has a more favorable balance between communication and computation. Specifically, our protocol has the lowest monetary cost of any known PSI protocol, when run over the Internet using cloud-based computing services (taking into account current rates for CPU + data). On slow networks (e.g., 10Mbps) our protocol is actually the fastest.

Our novel underlying technique is a variant of oblivious transfer (OT) extension that we call sparse OT extension. Conceptually it can be thought of as a communication-efficient multipoint oblivious PRF evaluation. Our sparse OT technique relies heavily on manipulating high-degree polynomials over large finite fields (i.e. elements whose representation requires hundreds of bits). We introduce extensive algorithmic and engineering improvements for interpolation and multi-point evaluation of such polynomials, which we believe will be of independent interest.

Finally, we present an extensive empirical comparison of state-of-the- art PSI protocols in several application scenarios and along several dimensions of measurement: running time, communication, peak memory consumption, and arguably the most relevant metric for practice monetary cost

Category / Keywords: cryptographic protocols / private set intersection, OT extension

Original Publication (with major differences): IACR-CRYPTO-2019

Date: received 2 Jun 2019

Contact author: rosulekm at eecs oregonstate edu

Available format(s): PDF | BibTeX Citation

Version: 20190603:072905 (All versions of this report)

Short URL: ia.cr/2019/634


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