Publication Type

Conference Proceeding Article

Version

publishedVersion

Publication Date

10-2019

Abstract

Due to the threat posed by quantum computers, a series of works investigate the security of cryptographic schemes in the quantum-accessible random oracle model (QROM) where the adversary can query the random oracle in superposition. In this paper, we present tighter security proofs of a generic transformations for key encapsulation mechanism (KEM) in the QROM in the multi-challenge setting, where the reduction loss is independent of the number of challenge ciphertexts. In particular, we introduce the notion of multi-challenge OW-CPA (mOW-CPA) security, which captures the one-wayness of the underlying public key encryption (PKE) under chosen plaintext attack in the multi-challenge setting. We show that the multi-challenge IND-CCA (mIND-CCA) security of KEM can be reduced to the mOW-CPA security of the underlying PKE scheme (with �-correctness) using transformation. Then we prove that the mOW-CPA security can be tightly reduced to the underlying post-quantum assumptions by showing the tight mOW-CPA security of two concrete PKE schemes based on LWE, where one is the Regev’s PKE scheme and the other is a variant of Frodo.

Keywords

KEM, QROM, CCA, Tight security

Discipline

Information Security

Research Areas

Cybersecurity

Areas of Excellence

Digital transformation

Publication

Proceedings of the 18th International Conference, CANS 2019, Fuzhou, China, October 25–27

First Page

141

Last Page

160

ISBN

9783030315788

Identifier

10.1007/978-3-030-31578-8_8

Publisher

Springer

City or Country

Cham

Copyright Owner and License

Authors

Additional URL

https://doi.org/10.1007/978-3-030-31578-8_8

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