Covert security with public verifiability: faster, leaner, and simpler

Cheng Hong, Jonathan Katz, Vladimir Kolesnikov, Wen jie Lu, Xiao Wang*

*Corresponding author for this work

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

1 Scopus citations

Abstract

The notion of covert security for secure two-party computation serves as a compromise between the traditional semi-honest and malicious security definitions. Roughly, covert security ensures that cheating behavior is detected by the honest party with reasonable probability (say, 1/2). It provides more realistic guarantees than semi-honest security with significantly less overhead than is required by malicious security. The rationale for covert security is that it dissuades cheating by parties that care about their reputation and do not want to risk being caught. But a much stronger disincentive is obtained if the honest party can generate a publicly verifiable certificate when cheating is detected. While the corresponding notion of publicly verifiable covert (PVC) security has been explored, existing PVC protocols are complex and less efficient than the best covert protocols, and have impractically large certificates. We propose a novel PVC protocol that significantly improves on prior work. Our protocol uses only “off-the-shelf” primitives (in particular, it avoids signed oblivious transfer) and, for deterrence factor 1/2, has only 20–40% overhead compared to state-of-the-art semi-honest protocols. Our protocol also has, for the first time, constant-size certificates of cheating (e.g., 354 bytes long at the 128-bit security level). As our protocol offers strong security guarantees with low overhead, we suggest that it is the best choice for many practical applications of secure two-party computation.

Original languageEnglish (US)
Title of host publicationAdvances in Cryptology – EUROCRYPT 2019 - 38th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings
EditorsYuval Ishai, Vincent Rijmen
PublisherSpringer Verlag
Pages97-121
Number of pages25
ISBN (Print)9783030176587
DOIs
Publication statusPublished - Jan 1 2019
Event38th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Eurocrypt 2019 - Darmstadt, Germany
Duration: May 19 2019May 23 2019

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume11478 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference38th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Eurocrypt 2019
CountryGermany
CityDarmstadt
Period5/19/195/23/19

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ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)

Cite this

Hong, C., Katz, J., Kolesnikov, V., Lu, W. J., & Wang, X. (2019). Covert security with public verifiability: faster, leaner, and simpler. In Y. Ishai, & V. Rijmen (Eds.), Advances in Cryptology – EUROCRYPT 2019 - 38th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings (pp. 97-121). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 11478 LNCS). Springer Verlag. https://doi.org/10.1007/978-3-030-17659-4_4