CryptoDB
Round-Efficient Composable Two-Party Quantum Computation
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| Conference: | ASIACRYPT 2025 |
| Abstract: | We study secure computation in the plain model against fully concurrent quantum adversaries. While classical simulation-based notions --- such as Super-Polynomial Simulation (SPS) security --- have enabled meaningful forms of concurrent security, very little is known about their quantum counterparts, particularly under standard polynomial-time hardness assumptions. Our main result is the first post-quantum two-party computation protocol that achieves concurrent SPS security, based solely on the minimal assumption of semi-honest post-quantum oblivious transfer (PQ-OT). Moreover, our protocol has constant round complexity when the underlying PQ-OT protocol is constant-round. This can be viewed as a post-quantum analog of the classical result by Garg et al. [Eurocrypt'12], but with a crucial difference: our security proof completely avoids rewinding, making it suitable for quantum settings where rewinding is notoriously challenging due to the no-cloning principle. By leveraging a compiler of Bartusek et al. [Crypto'21], we further extend our result to the fully quantum setting, yielding the first constant-round concurrent SPS two-party computation for {\em quantum} functionalities in the plain model. Additionally, we construct a two-round, public-coin, concurrent SPS post-quantum zero-knowledge protocol for languages in $\NP \cap \coNP$, under the quantum polynomial-time hardness of LWE. This result is notable even in the classical setting. |
BibTeX
@inproceedings{asiacrypt-2025-36156,
title={Round-Efficient Composable Two-Party Quantum Computation},
publisher={Springer-Verlag},
author={Vipul Goyal and Xiao Liang and Omkant Pandey and Yuhao Tang and Takashi Yamakawa},
year=2025
}