Paper 2019/1352

Spectral analysis of ZUC-256

Jing Yang, Thomas Johansson, and Alexander Maximov

Abstract

In this paper we develop a number of generic techniques and algorithms in spectral analysis of large linear approximations for use in cryptanalysis. We apply the developed tools for cryptanalysis of ZUC-256 and give a distinguishing attack with complexity around $2^{236}$. Although the attack is only $2^{20}$ times faster than exhaustive key search, the result indicates that ZUC-256 does not provide a source with full 256-bit entropy in the generated keystream, which would be expected from a 256-bit key. To the best of our knowledge, this is the first known academic attack on full ZUC-256 with a computational complexity that is below exhaustive key search.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Published by the IACR in FSE 2020
Keywords
ZUC-256Stream Cipher5G Mobile System Security
Contact author(s)
alexander maximov @ ericsson com
History
2020-02-19: revised
2019-11-27: received
See all versions
Short URL
https://ia.cr/2019/1352
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2019/1352,
      author = {Jing Yang and Thomas Johansson and Alexander Maximov},
      title = {Spectral analysis of {ZUC}-256},
      howpublished = {Cryptology {ePrint} Archive, Paper 2019/1352},
      year = {2019},
      url = {https://eprint.iacr.org/2019/1352}
}
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