Round-Optimal and Communication-Efficient Multiparty Computation

Michele Ciampi, Rafail Ostrovsky, Hendrik Waldner*, Vassilis Zikas

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract / Description of output

Typical approaches for minimizing the round complexity of multiparty computation (MPC) come at the cost of increased communication complexity (CC) or the reliance on setup assumptions. A notable exception is the recent work of Ananth et al. [TCC 2019], which used Functional Encryption (FE) combiners to obtain a round optimal (two-round) semi-honest MPC in the plain model with a CC proportional to the depth and input-output length of the circuit being computed—we refer to such protocols as circuit scalable. This leaves open the question of obtaining communication efficient protocols that are secure against malicious adversaries in the plain model, which we present in this work. Concretely, our two main contributions are: 1) We provide a round-preserving black-box compiler that compiles a wide class of MPC protocols into circuit-scalable maliciously secure MPC protocols in the plain model, assuming (succinct) FE combiners. 2) We provide a round-preserving black-box compiler that compiles a wide class of MPC protocols into circuit-independent—i.e., with a CC that depends only on the input-output length of the circuit—maliciously secure MPC protocols in the plain model, assuming Multi-Key Fully-Homomorphic Encryption (MFHE). Our constructions are based on a new compiler that turns a wide class of MPC protocols into k-delayed-input function MPC protocols (a notion we introduce), where the function that is being computed is specified only in the k-th round of the protocol. As immediate corollaries of our two compilers, we derive (1) the first round-optimal and circuit-scalable maliciously secure MPC, and (2) the first round-optimal and circuit-independent maliciously secure MPC in the plain model. The latter MPC achieves the best to-date CC for a round-optimal malicious MPC protocol. In fact, it is even communication-optimal when the output size of the function being evaluated is smaller than its input size (e.g., for boolean functions). All of our results are based on standard polynomial time assumptions.

Original languageEnglish
Title of host publicationAdvances in Cryptology – EUROCRYPT 2022 - 41st Annual International Conference on the Theory and Applications of Cryptographic Techniques, 2022, Proceedings
EditorsOrr Dunkelman, Stefan Dziembowski
PublisherSpringer, Cham
Pages65-95
Number of pages31
ISBN (Electronic)978-3-031-06944-4
ISBN (Print)978-3-031-06943-7
DOIs
Publication statusPublished - 25 May 2022
Event41st Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2022 - Trondheim, Norway
Duration: 30 May 20223 Jun 2022

Publication series

NameLecture Notes in Computer Science
PublisherSpringer Cham
Volume13275
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference41st Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2022
Country/TerritoryNorway
CityTrondheim
Period30/05/223/06/22

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