### Multiparty Reusable Non-Interactive Secure Computation

Fabrice Benhamouda and Huijia Lin

##### Abstract

Reducing interaction in Multiparty Computation (MPC) is a highly desirable goal in cryptography. It is known that 2-round MPC can be based on the minimal assumption of 2-round Oblivious Transfer (OT) [Benhamouda and Lin, Garg and Srinivasan, EC 2018], and 1-round MPC is impossible in general. In this work, we propose a natural hybrid'' model, called \textbf{multiparty reusable Non-Interactive Secure Computation Market (mrNISC)}. In this model, parties publish encodings of their private inputs $x_i$ at the beginning, once and for all. Later, any subset $I$ of them can compute \emph{on-the-fly} a function $f$ on their inputs $\vec x_I = {\{x_i\}}_{i \in I}$ by just sending a single message to a stateless evaluator, conveying the result $f(\vec x_I)$ and nothing else. Importantly, the input encodings can be \emph{reused} in any number of on-the-fly computations, and the same classical simulation security guaranteed by multi-round MPC, is achieved. In short, mrNISC has minimal yet tractable'' interaction pattern. We initiate the study of mrNISC on several fronts. First, we formalize the security of mrNISC protocols in both a UC definition and a game-based definition. Second, we construct mrNISC protocols in the plain model with semi-honest and semi-malicious security based on bilinear groups. Third, we demonstrate the power of mrNISC by showing two applications: non-interactive MPC (NIMPC) with reusable setup and a distributed version of program obfuscation. In addition, at the core of our construction of mrNISC is a witness encryption scheme for a special language that verifies Non-Interactive Zero-Knowledge (NIZK) proofs of the validity of computations over committed values, which we believe is of independent interest.

Note: 2021-07-01: various style improvements, comparison to on-the-fly MPC

Available format(s)
Category
Cryptographic protocols
Publication info
A major revision of an IACR publication in TCC 2020
DOI
10.1007/978-3-030-64378-2_13
Keywords
Multiparty Secure ComputationNon InteractiveWitness Encryption
Contact author(s)
rachel @ cs washington edu
fabrice benhamouda @ normalesup org
History
2021-07-01: revised
See all versions
Short URL
https://ia.cr/2020/221

CC BY

BibTeX

@misc{cryptoeprint:2020/221,
author = {Fabrice Benhamouda and Huijia Lin},
title = {Multiparty Reusable Non-Interactive Secure Computation},
howpublished = {Cryptology ePrint Archive, Paper 2020/221},
year = {2020},
doi = {10.1007/978-3-030-64378-2_13},
note = {\url{https://eprint.iacr.org/2020/221}},
url = {https://eprint.iacr.org/2020/221}
}

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