Cryptology ePrint Archive: Report 2020/1599

Function Secret Sharing for PSI-CA: With Applications to Private Contact Tracing

Samuel Dittmer and Yuval Ishai and Steve Lu and Rafail Ostrovsky and Mohamed Elsabagh and Nikolaos Kiourtis and Brian Schulte and Angelos Stavrou

Abstract: In this work we describe a token-based solution to Contact Tracing via Distributed Point Functions (DPF) and, more generally, Function Secret Sharing (FSS). The key idea behind the solution is that FSS natively supports secure keyword search on raw sets of keywords without a need for processing the keyword sets via a data structure for set membership. Furthermore, the FSS functionality enables adding up numerical payloads associated with multiple matches without additional interaction. These features make FSS an attractive tool for lightweight privacy-preserving searching on a database of tokens belonging to infected individuals.

Category / Keywords: cryptographic protocols / Private Set Intersection, Contact Tracing, Function Secret Sharing, Private Aggregation

Date: received 23 Dec 2020

Contact author: steve at stealthsoftwareinc com

Available format(s): PDF | BibTeX Citation

Version: 20201224:074147 (All versions of this report)

Short URL: ia.cr/2020/1599