### A New Approach to Post-Quantum Non-Malleability

##### Abstract

We provide the first $\mathit{constant}$-$\mathit{round}$ construction of post-quantum non-malleable commitments under the minimal assumption that $\mathit{post}$-$\mathit{quantum}$ $\mathit{one}$-$\mathit{way}$ $\mathit{functions}$ exist. We achieve the standard notion of non-malleability with respect to commitments. Prior constructions required $\Omega(\log^*\lambda)$ rounds under the same assumption. We achieve our results through a new technique for constant-round non-malleable commitments which is easier to use in the post-quantum setting. The technique also yields an almost elementary proof of security for constant-round non-malleable commitments in the classical setting, which may be of independent interest. As an application, when combined with existing work, our results yield the first constant-round post-quantum secure multiparty computation under the $\mathit{polynomial}$ hardness of quantum fully-homomorphic encryption and quantum learning with errors.

Available format(s)
Category
Foundations
Publication info
Preprint.
Keywords
Non-MalleablePost-QuantumConstant-Round
Contact author(s)
xiao crypto @ gmail com
omkant @ cs stonybrook edu
takashi yamakawa ga @ hco ntt co jp
History
2022-07-14: approved
See all versions
Short URL
https://ia.cr/2022/907

CC BY-NC-ND

BibTeX

@misc{cryptoeprint:2022/907,
author = {Xiao Liang and Omkant Pandey and Takashi Yamakawa},
title = {A New Approach to Post-Quantum Non-Malleability},
howpublished = {Cryptology ePrint Archive, Paper 2022/907},
year = {2022},
note = {\url{https://eprint.iacr.org/2022/907}},
url = {https://eprint.iacr.org/2022/907}
}

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