Cryptanalysis of a nonlinear filter-based stream cipher

Tim Beyne; Michiel Verbauwhede

Paper 2025/197

Cryptanalysis of a nonlinear filter-based stream cipher

Tim Beyne

, KU Leuven

Michiel Verbauwhede

, KU Leuven

Abstract

It is shown that the stream cipher proposed by Carlet and Sarkar in ePrint report 2025/160 is insecure. More precisely, one bit of the key can be deduced from a few keystream bytes. This property extends to an efficient key-recovery attack. For example, for the proposal with 80 bit keys, a few kilobytes of keystream material are sufficient to recover half of the key.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint.
Keywords: cryptanalysis stream cipher truncated differential
Contact author(s): tim beyne @ esat kuleuven be
michiel verbauwhede @ esat kuleuven be
History: 2025-02-11: revised; 2025-02-10: received; See all versions
Short URL: https://ia.cr/2025/197
License: CC BY

BibTeX

@misc{cryptoeprint:2025/197,
      author = {Tim Beyne and Michiel Verbauwhede},
      title = {Cryptanalysis of a nonlinear filter-based stream cipher},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/197},
      year = {2025},
      url = {https://eprint.iacr.org/2025/197}
}