Generic Compiler for Publicly Verifiable Covert Multi-Party Computation

Sebastian Faust, Carmit Hazay, David Kretzler, Benjamin Schlosser

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

5 Scopus citations

Abstract

Covert security has been introduced as a compromise between semi-honest and malicious security. In a nutshell, covert security guarantees that malicious behavior can be detected by the honest parties with some probability, but in case detection fails all bets are off. While the security guarantee offered by covert security is weaker than full-fledged malicious security, it comes with significantly improved efficiency. An important extension of covert security introduced by Asharov and Orlandi (ASIACRYPT’12) is public verifiability, which allows the honest parties to create a publicly verifiable certificate of malicious behavior. Public verifiability significantly strengthen covert security as the certificate allows punishment via an external party, e.g., a judge. Most previous work on publicly verifiable covert (PVC) security focuses on the two-party case, and the multi-party case has mostly been neglected. In this work, we introduce a novel compiler for multi-party PVC secure protocols with no private inputs. The class of supported protocols includes the preprocessing of common multi-party computation protocols that are designed in the offline-online model. Our compiler leverages time-lock encryption to offer high probability of cheating detection (often also called deterrence factor) independent of the number of involved parties. Moreover, in contrast to the only earlier work that studies PVC in the multi-party setting (CRYPTO’20), we provide the first full formal security analysis.

Original languageEnglish
Title of host publicationAdvances in Cryptology – EUROCRYPT 2021 - 40th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings
EditorsAnne Canteaut, François-Xavier Standaert
PublisherSpringer Science and Business Media Deutschland GmbH
Pages782-811
Number of pages30
ISBN (Print)9783030778859
DOIs
StatePublished - 2021
Event40th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2021 - Zagreb, Croatia
Duration: 17 Oct 202121 Oct 2021

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12697 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference40th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2021
Country/TerritoryCroatia
CityZagreb
Period17/10/2121/10/21

Bibliographical note

Publisher Copyright:
© 2021, International Association for Cryptologic Research.

Keywords

  • Covert security
  • Multi-party computation
  • Public verifiability
  • Time-lock puzzles

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