Cryptanalysis of Sfinks

Nicolas T.  Courtois

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Paper 2005/243

Cryptanalysis of Sfinks

Nicolas T. Courtois

Abstract

Sfinks is an LFSR-based stream cipher submitted to ECRYPT call for stream ciphers by Braeken, Lano, Preneel et al. The designers of Sfinks do not to include any protection against algebraic attacks. They rely on the so called "Algebraic Immunity", that relates to the complexity of a simple algebraic attack, and ignores other algebraic attacks. As a result, Sfinks is insecure.

Metadata

Available format(s): PDF PS
Category: Secret-key cryptography
Publication info: Published elsewhere. Unknown where it was published
Keywords: algebraic cryptanalysis stream ciphers nonlinear filters Boolean functions solving systems of multivariate equations fast algebraic attacks on stream ciphers
Contact author(s): courtois @ minrank org
History: 2005-07-31: revised; 2005-07-30: received; See all versions
Short URL: https://ia.cr/2005/243
License: CC BY

BibTeX

@misc{cryptoeprint:2005/243,
      author = {Nicolas T.  Courtois},
      title = {Cryptanalysis of Sfinks},
      howpublished = {Cryptology ePrint Archive, Paper 2005/243},
      year = {2005},
      note = {\url{https://eprint.iacr.org/2005/243}},
      url = {https://eprint.iacr.org/2005/243}
}