SoK: Outsourced Private Set Intersection

Sophie Hawkes; Christian Weinert

Paper 2026/080

SoK: Outsourced Private Set Intersection

Sophie Hawkes

, Royal Holloway University of London

Christian Weinert

, Royal Holloway University of London

Abstract

Private set intersection (PSI) protocols are an essential privacy-enhancing technology for many real-world use cases, ranging from mobile contact discovery to fraud detection. However, PSI executed directly between input parties can result in unreasonable performance overhead. This motivates the study of outsourced PSI, where clients delegate the heavy PSI operations to an untrusted (cloud) server. In this SoK, we introduce a framework of 12 distinct properties that characterize outsourced PSI protocols based on security, functionality, and efficiency. By analyzing 20 protocols through this framework, we provide a valuable resource and an interactive tool for researchers and practitioners to select the most suitable protocols for their specific requirements. Finally, we discuss research gaps between trends in regular PSI and the current state of outsourced PSI, identifying promising avenues for future work.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Published elsewhere. Minor revision. ACNS 2026
Keywords: Private Set Intersection Cloud Computing Outsourcing
Contact author(s): sophie hawkes 2022 @ live rhul ac uk
christian weinert @ rhul ac uk
History: 2026-01-22: approved; 2026-01-18: received; See all versions
Short URL: https://ia.cr/2026/080
License: CC BY

BibTeX

@misc{cryptoeprint:2026/080,
      author = {Sophie Hawkes and Christian Weinert},
      title = {{SoK}: Outsourced Private Set Intersection},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/080},
      year = {2026},
      url = {https://eprint.iacr.org/2026/080}
}