Cryptanalysis of Sfinks

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 include any real protection against algebraic attacks other than the so called “Algebraic Immunity”, that relates to the complexity of a simple algebraic attack, and ignores more elaborate attacks. As a result, Sfinks is insecure.

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