Valiant’s universal circuits revisited: An overall improvement and a lower bound

Shuoyao Zhao, Yu Yu, Jiang Zhang, Hanlin Liu

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

6 Scopus citations

Abstract

A universal circuit (UC) is a general-purpose circuit that can simulate arbitrary circuits (up to a certain size n). At STOC 1976 Valiant presented a graph theoretic approach to the construction of UCs, where a UC is represented by an edge universal graph (EUG) and is recursively constructed using a dedicated graph object (referred to as supernode). As a main end result, Valiant constructed a 4-way supernode of size 19 and an EUG of size 4.75nlogn (omitting smaller terms), which remained the most size-efficient even to this day (after more than 4 decades). Motivated by the emerging applications of UCs in various privacy preserving computation scenarios, we revisit Valiant’s universal circuits, and propose a 4-way supernode of size 18, and an EUG of size 4.75nlogn. As confirmed by our implementations, we reduce the size of universal circuits (and the number of AND gates) by more than 5% in general, and thus improve upon the efficiency of UC-based cryptographic applications accordingly. Our approach to the design of optimal supernodes is computer aided (rather than by hand as in previous works), which might be of independent interest. As a complement, we give lower bounds on the size of EUGs and UCs in Valiant’s framework, which significantly improves upon the generic lower bound on UC size and therefore reduces the gap between theory and practice of universal circuits.

Original languageEnglish
Title of host publicationAdvances in Cryptology – ASIACRYPT 2019 - 25th International Conference on the Theory and Application of Cryptology and Information Security, 2019, Proceedings
EditorsSteven D. Galbraith, Shiho Moriai
PublisherSpringer Science and Business Media Deutschland GmbH
Pages401-425
Number of pages25
ISBN (Print)9783030345778
DOIs
StatePublished - 2019
Externally publishedYes
Event25th International Conference on the Theory and Applications of Cryptology and Information Security, ASIACRYPT 2019 - Kobe, Japan
Duration: 8 Dec 201912 Dec 2019

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume11921 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference25th International Conference on the Theory and Applications of Cryptology and Information Security, ASIACRYPT 2019
Country/TerritoryJapan
CityKobe
Period8/12/1912/12/19

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