### QCCA-Secure Generic Transformations in the Quantum Random Oracle Model

##### Abstract

The post-quantum security of cryptographic systems assumes that the quantum adversary only receives the classical result of computations with the secret key. Furthermore, if the adversary is able to obtain a superposition state of the result, it is unknown whether the post-quantum secure schemes still remain secure. In this paper, we formalize one class of public-key encryption schemes, named oracle-masked schemes, relative to random oracles. For each oracle-masked scheme, we design a preimage extraction procedure and prove that it simulates the quantum decryption oracle with a certain loss. We also observe that the implementation of the preimage extraction procedure for some oracle-masked schemes does not need to take the secret key as input. This contributes to the IND-qCCA security proof of these schemes in the quantum random oracle model (QROM). As an application, we prove the IND-qCCA security of schemes obtained by the Fujisaki-Okamoto (FO) transformation and REACT transformation in the QROM, respectively. Notably, our security reduction for FO transformation is tighter than the reduction given by Zhandry (Crypto 2019).

Available format(s)
Category
Public-key cryptography
Publication info
Preprint.
Keywords
FO transformation REACT transformation quantum random oracle model quantum chosen ciphertext security
Contact author(s)
shantianshu @ iie ac cn
gejiangxia @ iie ac cn
xuerui @ iie ac cn
History
2022-09-19: approved
See all versions
Short URL
https://ia.cr/2022/1235

CC BY

BibTeX

@misc{cryptoeprint:2022/1235,
author = {Tianshu Shan and Jiangxia Ge and Rui Xue},
title = {QCCA-Secure Generic Transformations in the Quantum Random Oracle Model},
howpublished = {Cryptology ePrint Archive, Paper 2022/1235},
year = {2022},
note = {\url{https://eprint.iacr.org/2022/1235}},
url = {https://eprint.iacr.org/2022/1235}
}

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