Cryptanalysis of ARX-based White-box Implementations

Authors

  • Alex Biryukov University of Luxembourg, Esch-sur-Alzette, Luxembourg
  • Baptiste Lambin University of Luxembourg, Esch-sur-Alzette, Luxembourg
  • Aleksei Udovenko University of Luxembourg, Esch-sur-Alzette, Luxembourg

DOI:

https://doi.org/10.46586/tches.v2023.i3.97-135

Keywords:

White-box cryptography, Cryptanalysis, Algebraic attacks, Decomposition attacks

Abstract

At CRYPTO’22, Ranea, Vandersmissen, and Preneel proposed a new way to design white-box implementations of ARX-based ciphers using so-called implicit functions and quadratic-affine encodings. They suggest the Speck block-cipher as an example target.
In this work, we describe practical attacks on the construction. For the implementation without one of the external encodings, we describe a simple algebraic key recovery attack. If both external encodings are used (the main scenario suggested by the authors), we propose optimization and inversion attacks, followed by our main result - a multiple-step round decomposition attack and a decomposition-based key recovery attack.
Our attacks only use the white-box round functions as oracles and do not rely on their description. We implemented and verified experimentally attacks on white-box instances of Speck-32/64 and Speck-64/128. We conclude that a single ARX-round is too weak to be used as a white-box round.

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Published

2023-06-09

Issue

Section

Articles

How to Cite

Cryptanalysis of ARX-based White-box Implementations. (2023). IACR Transactions on Cryptographic Hardware and Embedded Systems, 2023(3), 97-135. https://doi.org/10.46586/tches.v2023.i3.97-135