### Low-Communication Multiparty Triple Generation for SPDZ from Ring-LPN

Damiano Abram and Peter Scholl

##### Abstract

The SPDZ protocol for multi-party computation relies on a correlated randomness setup consisting of authenticated, multiplication triples. A recent line of work by Boyle et al. (Crypto 2019, Crypto 2020) has investigated the possibility of producing this correlated randomness in a silent preprocessing phase, which involves a “small” setup protocol with less communication than the total size of the triples being produced. These works do this using a tool called a pseudorandom correlation generator (PCG), which allows a large batch of correlated randomness to be compressed into a set of smaller, correlated seeds. However, existing methods for compressing SPDZ triples only apply to the 2-party setting. In this work, we construct a PCG for producing SPDZ triples over large prime fields in the multi-party setting. The security of our PCG is based on the ring-LPN assumption over fields, similar to the work of Boyle et al. (Crypto 2020) in the 2-party setting. We also present a corresponding, actively secure setup protocol, which can be used to generate the PCG seeds and instantiate SPDZ with a silent preprocessing phase. As a building block, which may be of independent interest, we construct a new type of 3-party distributed point function supporting outputs over arbitrary groups (including large prime order), as well as an efficient protocol for setting up our DPF keys with active security.

Available format(s)
Category
Cryptographic protocols
Publication info
A major revision of an IACR publication in PKC 2022
Keywords
PCGSPDZDPFMPC
Contact author(s)
damiano abram @ cs au dk
peter scholl @ cs au dk
History
Short URL
https://ia.cr/2022/315

CC BY

BibTeX

@misc{cryptoeprint:2022/315,
author = {Damiano Abram and Peter Scholl},
title = {Low-Communication Multiparty Triple Generation for SPDZ from Ring-LPN},
howpublished = {Cryptology ePrint Archive, Paper 2022/315},
year = {2022},
note = {\url{https://eprint.iacr.org/2022/315}},
url = {https://eprint.iacr.org/2022/315}
}

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