Communication-Efficient (Client-Aided) Secure Two-Party Protocols and Its Application

Satsuya Ohata, Koji Nuida

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

21 Citations (Scopus)


Secure multi-party computation (MPC) allows a set of parties to compute a function jointly while keeping their inputs private. Compared with the MPC based on garbled circuits, some recent research results show that MPC based on secret sharing (SS) works at a very high speed. Moreover, SS-based MPC can be easily vectorized and achieve higher throughput. In SS-based MPC, however, we need many communication rounds for computing concrete protocols like equality check, less-than comparison, etc. This property is not suited for large-latency environments like the Internet (or WAN). In this paper, we construct semi-honest secure communication-efficient two-party protocols. The core technique is Beaver triple extension, which is a new tool for treating multi-fan-in gates, and we also show how to use it efficiently. We mainly focus on reducing the number of communication rounds, and our protocols also succeed in reducing the number of communication bits (in most cases). As an example, we propose a less-than comparison protocol (under practical parameters) with three communication rounds. Moreover, the number of communication bits is also fewer. As a result, total online execution time is shorter than the previous work adopting the same settings. Although the computation costs of our protocols are more expensive than those of previous work, we confirm via experiments that such a disadvantage has small effects on the whole online performance in the typical WAN environments.

Original languageEnglish
Title of host publicationFinancial Cryptography and Data Security - 24th International Conference, FC 2020, Revised Selected Papers
EditorsJoseph Bonneau, Nadia Heninger
Number of pages17
ISBN (Print)9783030512798
Publication statusPublished - 2020
Externally publishedYes
Event24th International Conference on Financial Cryptography and Data Security, FC 2020 - Kota Kinabalu, Malaysia
Duration: Feb 10 2020Feb 14 2020

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12059 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference24th International Conference on Financial Cryptography and Data Security, FC 2020
CityKota Kinabalu

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • General Computer Science


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