Laconic Private Set-Intersection From Pairings

Abstract

Private set-intersection (PSI) is one of the most practically relevant special-purpose secure multiparty computation tasks, as it is motivated by many real-world applications. In this paper we present a new private set-intersection protocol which is laconic, meaning that the protocol only has two rounds and that the first message is independent of the set sizes. Laconic PSI can be useful in applications, where servers with large sets would like to learn the intersection of their set with smaller sets owned by resource-constrained clients and where multiple rounds of interactions are not possible. Previously, practically relevant laconic PSI protocols were only known from factoring-type assumptions. The contributions of this work are twofold: 1) We present the first laconic PSI protocol based on assumptions over pairing-friendly elliptic curves; and 2) For the first time we provide empirical evaluation of any laconic PSI protocol by carefully implementing and optimizing both our and previous protocols. Our experimental results shows that our protocol outperforms prior laconic PSI protocols.