### Post-Quantum Security of the (Tweakable) FX Construction, and Applications

##### Abstract

The FX construction provides a way to increase the effective key length of a block cipher E. We prove security of a tweakable version of the FX construction in the post-quantum setting, i.e., against a quantum attacker given only classical access to the secretly keyed construction while retaining quantum access to E, a setting that seems to be the most relevant one for real-world applications. We then use our results to prove post-quantum security—in the same model—of the (plain) FX construction, Elephant (a finalist of NIST's lightweight cryptography standardization effort), and Chaskey (an ISO-standardized lightweight MAC).

Available format(s)
Category
Secret-key cryptography
Publication info
Preprint.
Contact author(s)
galagic @ umd edu
cbai1 @ umd edu
jkatz2 @ gmail com
chmaj @ dtu dk
patrick struck @ ur de
History
2022-08-29: approved
See all versions
Short URL
https://ia.cr/2022/1097

CC BY

BibTeX

@misc{cryptoeprint:2022/1097,
author = {Gorjan Alagic and Chen Bai and Jonathan Katz and Christian Majenz and Patrick Struck},
title = {Post-Quantum Security of the (Tweakable) FX Construction, and Applications},
howpublished = {Cryptology ePrint Archive, Paper 2022/1097},
year = {2022},
note = {\url{https://eprint.iacr.org/2022/1097}},
url = {https://eprint.iacr.org/2022/1097}
}

Note: In order to protect the privacy of readers, eprint.iacr.org does not use cookies or embedded third party content.