Paper 2022/1437

Secure Multiparty Computation from Threshold Encryption based on Class Groups

Lennart Braun, Aarhus University
Ivan Damgård, Aarhus University
Claudio Orlandi, Aarhus University
Abstract

We construct the first actively-secure threshold version of the cryptosystem based on class groups from the so-called CL framework (Castagnos and Laguillaumie, 2015). We then show how to use our threshold scheme to achieve general secure multiparty computation (MPC) with only transparent set-up, i.e., with no secret trapdoors involved. To achieve this, we also design a new zero-knowledge protocol for proving multiplicative relations between encrypted values. As a result, the zero-knowledge proofs needed to get active security add only a constant factor overhead. Finally, we explain how to adapt our protocol for the so called "You-Only-Speak-Once" (YOSO) setting, which is a very promising recent approach for performing MPC over a blockchain.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
Keywords
mpc zero-knowledge threshold encryption class groups
Contact author(s)
braun @ cs au dk
ivan @ cs au dk
orlandi @ cs au dk
History
2022-10-24: approved
2022-10-21: received
See all versions
Short URL
https://ia.cr/2022/1437
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2022/1437,
      author = {Lennart Braun and Ivan Damgård and Claudio Orlandi},
      title = {Secure Multiparty Computation from Threshold Encryption based on Class Groups},
      howpublished = {Cryptology ePrint Archive, Paper 2022/1437},
      year = {2022},
      note = {\url{https://eprint.iacr.org/2022/1437}},
      url = {https://eprint.iacr.org/2022/1437}
}
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