Paper 2016/826 Original: eprint.iacr.org/2016/826 ↗

Rotational Cryptanalysis in the Presence of Constants

Tomer Ashur
Yunwen Liu
Abstract

Rotational cryptanalysis is a statistical method for attacking ARX constructions. It was previously shown that ARX-C, i.e., ARX with the injection of constants can be used to implement any function. In this paper we investigate how rotational cryptanalysis is affected when constants are injected into the state. We introduce the notion of an RX-difference, generalizing the idea of a rotational difference. We show how RX-differences behave around modular addition, and give a formula to calculate their transition probability. We experimentally verify the for- mula using Speck32/64, and present a 7-round distinguisher based on RX-differences. We then discuss two types of constants: round constants, and constants which are the result of using a fixed key, and provide recommendations to designers for optimal choice of parameters.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Preprint.
History
2016-09-19: last updated
2016-08-30: published
Short URL
https://ia.cr/2016/826
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2016/826,
      author = {Tomer Ashur and Yunwen Liu},
      title = {Rotational Cryptanalysis in the Presence of Constants},
      howpublished = {Cryptology {ePrint} Archive, Paper 2016/826},
      year = {2016},
      url = {https://eprint.iacr.org/2016/826}
}
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