Paper 2019/634

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

Benny Pinkas, Mike Rosulek, Ni Trieu, and Avishay Yanai


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

Available format(s)
Cryptographic protocols
Publication info
A major revision of an IACR publication in CRYPTO 2019
private set intersectionOT extension
Contact author(s)
rosulekm @ eecs oregonstate edu
2019-06-03: received
Short URL
Creative Commons Attribution


      author = {Benny Pinkas and Mike Rosulek and Ni Trieu and Avishay Yanai},
      title = {SpOT-Light: Lightweight Private Set Intersection from Sparse OT Extension},
      howpublished = {Cryptology ePrint Archive, Paper 2019/634},
      year = {2019},
      note = {\url{}},
      url = {}
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