Earn While You Reveal: Private Set Intersection that Rewards Participants

TL;DR

This paper introduces Anesidora, a multi-party private set intersection protocol that incentivizes participants by rewarding them for contributing their private sets, while maintaining efficiency and security against collusion.

Contribution

It presents the first PSI protocol that rewards participants for their input contribution, addressing privacy costs and incentivization in multi-party settings.

Findings

Efficient linear complexity in computation and communication

Secure against active collusion of majority parties

First protocol to incentivize input contribution in PSI

Abstract

In Private Set Intersection protocols (PSIs), a non-empty result always reveals something about the private input sets of the parties. Moreover, in various variants of PSI, not all parties necessarily receive or are interested in the result. Nevertheless, to date, the literature has assumed that those parties who do not receive or are not interested in the result still contribute their private input sets to the PSI for free, although doing so would cost them their privacy. In this work, for the first time, we propose a multi-party PSI, called "Anesidora", that rewards parties who contribute their private input sets to the protocol. Anesidora is efficient; it mainly relies on symmetric key primitives and its computation and communication complexities are linear with the number of parties and set cardinality. It remains secure even if the majority of parties are corrupted by active colluding adversaries.