Multiparty Private Set Intersection from Multiparty Homomorphic Encryption

Summary

We revisit the problem of constructing protocols for multiparty private set intersection (MPSI) in light of the recent advances in multiparty homomorphic encryption (MHE). In MPSI, 𝑁 ≥ 2 parties jointly compute the intersection of their respective private set. Kissner and Song proposed an MHE-based MPSI scheme in 2005, but their approach was limited by the then-available HE schemes. Today, however, MHE schemes have become both more versatile and more efficient. As an early result, we implemented the MPSI approach of Kissner et al. with the recently proposed Helium framework (CCS 2024) for MHE-based MPC. We show that even this simple protocol can outperform the state-of-the-art implementation (in the passive-adversary setting) by Kolesnikov et al. (CCS 2017), both in terms of latency and communication cost.