International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Programmable Distributed Point Functions

Victor I. Kolobov , Technion
Elette Boyle , IDC Herzliya
Niv Gilboa , Ben-Gurion University
Yuval Ishai , Technion
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Conference: CRYPTO 2022
Abstract: A distributed point function (DPF) is a cryptographic primitive that enables compressed additive sharing of a secret unit vector across two or more parties. Despite growing ubiquity within applications and notable research efforts, the best 2-party DPF construction to date remains the tree-based construction from (Boyle et al, CCS’16), with no significantly new approaches since. We present a new framework for 2-party DPF construction, which applies in the setting of feasible (polynomial-size) domains. This captures in particular all DPF applications in which the keys are expanded to the full domain. Our approach is motivated by a strengthened notion we put forth, of programmable DPF (PDPF): in which a short, input-independent “offline” key can be reused for sharing many point functions. – PDPF from OWF. We construct a PDPF for feasible domains from the minimal assumption that one-way functions exist, where the second “online” key size is polylogarithmic in the domain size N. Our approach offers multiple new efficiency features and applications: – Privately puncturable PRFs. Our PDPF gives the first OWF-based privately puncturable PRFs (for feasible domains) with sublinear keys. – O(1)-round distributed DPF Gen. We obtain a (standard) DPF with polylog-size keys that admits an analog of Doerner-shelat (CCS’17) distributed key generation, requiring only O(1) rounds (versus log N). – PCG with 1 short key. Compressing useful correlations for secure computation, where one key size is of minimal size. This provides up to exponential communication savings in some application scenarios.
Video from CRYPTO 2022
  title={Programmable Distributed Point Functions},
  author={Victor I. Kolobov and Elette Boyle and Niv Gilboa and Yuval Ishai},