Paper 2026/1532
Just-in-Time-OPRFs and a Modular Framework for Fast Private Set Intersection
, University of California, San Diego, University of California, San Diego, Helmholtz Center for Information SecurityAbstract
This paper gives a modular and unified framework within which to derive fast protocols for Private Set Intersection (PSI). At the core of this is a new primitive, that we define, and that we call a Just-In-Time OPRF (JIT-OPRF). We show how to obtain PSI generically from any JIT-OPRF, and then how to obtain JIT-OPRFs from Oblivious Transfer (OT) and Vector Oblivious Linear Evaluation (VOLE). We recover as special cases PSI protocols in the literature based on these two assumptions. Our results and proofs throughout are concrete rather than asymptotic, with explicit bounds that allow one to determine security parameters to achieve a desired level (e.g.~128 bits) of proven security in practice. Our results show interesting differences in the concrete security of OT and VOLE based PSI. Beyond the practical contribution of concrete-security, our work adds conceptual simplicity to this area, and opens the door to new PSI protocols via the construction of new JIT-OPRFs.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- A major revision of an IACR publication in CRYPTO 2026
- Keywords
- PSIOPRFproof tightness
- Contact author(s)
-
mbellare @ ucsd edu
riranjan @ ucsd edu
riepel @ cispa de - History
- 2026-07-30: approved
- 2026-07-26: received
- See all versions
- Short URL
- https://ia.cr/2026/1532
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2026/1532,
author = {Mihir Bellare and Rishabh Ranjan and Doreen Riepel},
title = {Just-in-Time-{OPRFs} and a Modular Framework for Fast Private Set Intersection},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/1532},
year = {2026},
url = {https://eprint.iacr.org/2026/1532}
}
