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 language | English |
|---|---|
| Title of host publication | Advances in Cryptology – EUROCRYPT 2021 - 40th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings |
| Editors | Anne Canteaut, François-Xavier Standaert |
| Publisher | Springer Science and Business Media Deutschland GmbH |
| Pages | 782-811 |
| Number of pages | 30 |
| ISBN (Print) | 9783030778859 |
| DOIs | |
| State | Published - 2021 |
| Event | 40th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2021 - Zagreb, Croatia Duration: 17 Oct 2021 → 21 Oct 2021 |
Publication series
| Name | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) |
|---|---|
| Volume | 12697 LNCS |
| ISSN (Print) | 0302-9743 |
| ISSN (Electronic) | 1611-3349 |
Conference
| Conference | 40th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2021 |
|---|---|
| Country/Territory | Croatia |
| City | Zagreb |
| Period | 17/10/21 → 21/10/21 |
Bibliographical note
Publisher Copyright:© 2021, International Association for Cryptologic Research.
Funding
Acknowledgments. The first, third, and fourth authors were supported by the German Federal Ministry of Education and Research (BMBF) iBlockchain project (grant nr. 16KIS0902), by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) SFB 1119 – 236615297 (CROSSING Project S7), by the BMBF and the Hessian Ministry of Higher Education, Research, Science and the Arts within their joint support of the National Research Center for Applied Cybersecurity ATHENE, and by Robert Bosch GmbH, by the Economy of Things Project. The second author was supported by the BIU Center for Research in Applied Cryptography and Cyber Security in conjunction with the Israel National Cyber Bureau in the Prime Minister’s Office, and by ISF grant No. 1316/18.
| Funders | Funder number |
|---|---|
| Hessian Ministry of Higher Education, Research, Science and the Arts | |
| National Research Center for Applied Cybersecurity ATHENE | |
| Robert Bosch | |
| Deutsche Forschungsgemeinschaft | SFB 1119 – 236615297 |
| Bundesministerium für Bildung und Forschung | 16KIS0902 |
| Israel Science Foundation | 1316/18 |
Keywords
- Covert security
- Multi-party computation
- Public verifiability
- Time-lock puzzles