Best of Both Worlds: Revisiting the Spymasters Double Agent Problem

Anasuya Acharya; Carmit Hazay; Oxana Poburinnaya; Muthuramakrishnan Venkitasubramaniam

doi:10.1007/978-3-031-38557-5_11

Best of Both Worlds: Revisiting the Spymasters Double Agent Problem

Anasuya Acharya, Carmit Hazay, Oxana Poburinnaya, Muthuramakrishnan Venkitasubramaniam

Bar-Ilan University - The Alexander Kofkin Faculty of Engineering

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

Abstract

This work introduces the notion of secure multiparty computation: MPC with fall-back security. Fall-back security for an n-party protocol is defined with respect to an adversary structure Z wherein security is guaranteed in the presence of both a computationally unbounded adversary with adversary structure Z, and a computationally bounded adversary corrupting an arbitrarily large subset of the parties. This notion was considered in the work of Chaum (Crypto 89) via the Spymaster’s double agent problem where he showed a semi-honest secure protocol for the honest majority adversary structure. Our first main result is a compiler that can transform any n-party protocol that is semi-honestly secure with statistical security tolerating an adversary structure Z to one that (additionally) provides semi-honest fall-back security w.r.t Z. The resulting protocol has optimal round complexity, up to a constant factor, and is optimal in assumptions and the adversary structure. Our second result fully characterizes when malicious fall-back security is feasible. More precisely, we show that malicious fallback secure protocol w.r.t Z exists if and only if Z admits unconditional MPC against a semi-honest adversary (namely, iff Z∈ Q² ).

Original language	English
Title of host publication	Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings
Editors	Helena Handschuh, Anna Lysyanskaya
Publisher	Springer Science and Business Media Deutschland GmbH
Pages	328-359
Number of pages	32
ISBN (Print)	9783031385568
DOIs	https://doi.org/10.1007/978-3-031-38557-5_11
State	Published - 2023
Event	Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings - Santa Barbara, United States Duration: 20 Aug 2023 → 24 Aug 2023

Publication series

Name	Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume	14081 LNCS
ISSN (Print)	0302-9743
ISSN (Electronic)	1611-3349

Conference

Conference	Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings
Country/Territory	United States
City	Santa Barbara
Period	20/08/23 → 24/08/23

Bibliographical note

Publisher Copyright:
© 2023, International Association for Cryptologic Research.

Funding

Acknowledgments. Anasuya Acharya and Carmit Hazay are supported by ISF grant No. 1316/18. Carmit Hazay is also supported by the Algorand Centres of Excellence programme managed by Algorand Foundation. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of Algorand Foundation. The fourth author was supported by a JPMorgan Chase Faculty Research Award, Technology, and Humanity Fund from the McCourt School of Public Policy at Georgetown University, and a Google Research Award. Acknowledgements. Research supported in part by an Alon Young Faculty Fellowship, by a grant from the Israel Science Foundation (ISF Grant No. 1774/20), and by a grant from the US-Israel Binational Science Foundation and the US National Science Foundation (BSF-NSF Grant No. 2020643). 2055694. Vassilis Zikas’s research is supported in part by NSF grant no. 2055599 and by Sunday Group. The authors are also supported by the Algorand Centres of Excellence programme managed by Algorand Foundation. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of Algorand Foundation. Grant. This material is based upon work supported by the Defense Advanced Research Projects Agency through Award HR00112020024. A. Srinivasan was supported in part by a SERB startup grant and Google India Research Award. Acknowledgment. Y. Ishai was supported in part by ERC Project NTSC (742754), BSF grant 2018393, ISF grant 2774/20, and a Google Faculty Research Award. D. Khu-rana was supported in part by NSF CAREER CNS-2238718 and DARPA SIEVE. A. Sahai was supported in part from a Simons Investigator Award, DARPA SIEVE award, NTT Research, NSF Frontier Award 1413955, BSF grant 2012378, a Xerox Faculty Research Award, a Google Faculty Research Award, and an Okawa Foundation Research tial privacy in the shuﬄe model and the anonymous reviewers for their comments. Y. Ishai and E. Kushilevitz were supported by ISF grant 2774/20 and BSF grant 2018393. Y. Ishai was additionally supported by ERC Project NTSC (742754). Acknowledgments. Ran Cohen’s research is supported in part by NSF grant no. 2055568. Juan Garay’s research is supported in part by NSF grants no. 2001082 and G. Garimella, M. Rosulek and J. Singh—Authors partially supported by NSF award S2356A. Acknowledgements. D. Boneh is supported by NSF, the DARPA SIEVE program, the Simons Foundation, UBRI, and NTT Research. E. Boyle is supported by AFOSR Award FA9550-21-1-0046, ERC Project HSS (852952), and a Google Research Award. H. Corrigan-Gibbs is supported by Capital One, Facebook, Google, Mozilla, Seagate, MIT’s FinTech@CSAIL Initiative, and NSF Award CNS-2054869. N. Gilboa is supported by ISF grant 2951/20, ERC grant 876110, and a grant by the BGU Cyber Center. Y. Ishai is supported by ERC Project NTSC (742754), BSF grant 2018393, and ISF grant 2774/20. Opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of DARPA. Acknowledgments. The research described in this paper received funding from: the Concordium Blockhain Research Center, Aarhus University, Denmark; the Carlsberg Foundation under the Semper Ardens Research Project CF18-112 (BCM); the European Research Council (ERC) under the European Unions’s Horizon 2020 research and innovation programme under grant agreement No 803096 (SPEC); the Danish Independent Research Council under Grant-ID DFF-0165-00107B (C3PO). ritos and quesadillas. He also thanks the Aarhus Crypto Group and the people at NTT Research for being amazing humans (independently of their success in research). The work of Damiano Abram was carried out during an internship funded by NTT Research. Acknowledgements. We would like to thank Alin Tomescu, Kobi Gurkan, Julian Loss, and Renas Bacho for many insightful discussions. Gilad Stern was supported by the HUJI Federmann Cyber Security Research Center in conjunction with the Israel National Cyber Directorate (INCD) in the Prime Minister’s Office. Acknowledgements. Pedro Branco was partially funded by the German Federal Ministry of Education and Research (BMBF) in the course of the 6GEM research hub under grant number 16KISK038. Nico Döttling: Funded by the European Union (ERC, LACONIC, 101041207). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. Akshayaram Srinivasan was supported in part by a SERB startup grant and Google India Research Award. Acknowledgements. This work is funded in part by National Science Foundation award 2143058.

Funders	Funder number
Algorand Foundation
BSF-NSF	2020643
European Unions’s Horizon 2020 research and innovation programme	803096
Google India Research Award
JPMorgan
McCourt School of Public Policy
NTSC	742754
Sunday Group
UBRI
US-Israel BSF	2015782
National Science Foundation	2001082, CNS-2001096, CNS-2154174, 2055599, CCF-2220450, CNS-2238718, S2356A, CNS-2026774, 2055568, 2143058, CNS-2246355
Air Force Office of Scientific Research	FA9550-21-1-0046
Defense Advanced Research Projects Agency	HR0011-20-2-0025, HR00112020024
Simons Foundation
Microsoft
Cisco Systems
Google	CNS-2054869
Aarhus Universitet
Georgetown University
NTT Research	1413955, 2012378
European Commission	852952
United States-Israel Binational Science Foundation	2018393, 2774/20
Science and Engineering Research Board
Bundesministerium für Bildung und Forschung	16KISK038
Carlsbergfondet	CF18-112
Israel Science Foundation	1774/20, 876110, 2951/20, 1316/18
Okawa Foundation for Information and Telecommunications
Danmarks Frie Forskningsfond	DFF-0165-00107B
Ben-Gurion University of the Negev

Keywords

Best of Both Worlds
MPC Protocols Compiler
MPC with Fall-back Security

Access to Document

10.1007/978-3-031-38557-5_11

Cite this

Acharya, A., Hazay, C., Poburinnaya, O., & Venkitasubramaniam, M. (2023). Best of Both Worlds: Revisiting the Spymasters Double Agent Problem. In H. Handschuh, & A. Lysyanskaya (Eds.), Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings (pp. 328-359). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 14081 LNCS). Springer Science and Business Media Deutschland GmbH. https://doi.org/10.1007/978-3-031-38557-5_11

Acharya, Anasuya ; Hazay, Carmit ; Poburinnaya, Oxana et al. / Best of Both Worlds : Revisiting the Spymasters Double Agent Problem. Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings. editor / Helena Handschuh ; Anna Lysyanskaya. Springer Science and Business Media Deutschland GmbH, 2023. pp. 328-359 (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)).

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Acharya, A, Hazay, C, Poburinnaya, O & Venkitasubramaniam, M 2023, Best of Both Worlds: Revisiting the Spymasters Double Agent Problem. in H Handschuh & A Lysyanskaya (eds), Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings. Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), vol. 14081 LNCS, Springer Science and Business Media Deutschland GmbH, pp. 328-359, Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings, Santa Barbara, United States, 20/08/23. https://doi.org/10.1007/978-3-031-38557-5_11

Best of Both Worlds: Revisiting the Spymasters Double Agent Problem. / Acharya, Anasuya; Hazay, Carmit; Poburinnaya, Oxana et al.
Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings. ed. / Helena Handschuh; Anna Lysyanskaya. Springer Science and Business Media Deutschland GmbH, 2023. p. 328-359 (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 14081 LNCS).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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Acharya A, Hazay C, Poburinnaya O, Venkitasubramaniam M. Best of Both Worlds: Revisiting the Spymasters Double Agent Problem. In Handschuh H, Lysyanskaya A, editors, Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings. Springer Science and Business Media Deutschland GmbH. 2023. p. 328-359. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)). doi: 10.1007/978-3-031-38557-5_11