### Algebraic attacks on block ciphers using quantum annealing

Elżbieta Burek, Michał Misztal, and Michał Wroński

##### Abstract

This paper presents method for transformation of algebraic equations of symmetric cipher into the QUBO problem. After transformation of given equations $f_1, f_2, \dots, f_n$ to equations over integers $f'_1, f'_2, \dots, f'_n$, one has to linearize each, obtaining $f'_{lin_i}=lin(f'_i)$, where $lin$ denotes linearization operation. Finally, one can obtain problem in the QUBO form as $\left( f'_{lin_1} \right)^2+\dots+\left( f'_{lin_n} \right)^2+Pen$, where $Pen$ denotes penalties obtained during linearization of equations and $n$ is the number of equations. In this paper, we show examples of the transformation of some block ciphers to the QUBO problem. What is more, we present the results of the transformation of the full AES-128 cipher to the QUBO problem, where the number of variables of equivalent QUBO problem is equal to $237,915$, which means, at least theoretically, that problem may be solved using the D-Wave Advantage quantum annealing computer. Unfortunately, it is hard to estimate the time this process would require.

Available format(s)
Category
Secret-key cryptography
Publication info
Preprint. MINOR revision.
Keywords
CryptanalysisAESsymmetric ciphersalgebraic attacksquantum annealing
Contact author(s)
elzbieta burek @ wat edu pl
michal misztal @ wat edu pl
michal wronski @ wat edu pl
History
Short URL
https://ia.cr/2021/620

CC BY

BibTeX

@misc{cryptoeprint:2021/620,
author = {Elżbieta Burek and Michał Misztal and Michał Wroński},
title = {Algebraic attacks on block ciphers using quantum annealing},
howpublished = {Cryptology ePrint Archive, Paper 2021/620},
year = {2021},
note = {\url{https://eprint.iacr.org/2021/620}},
url = {https://eprint.iacr.org/2021/620}
}

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