cryptography Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adve ...

, F-FCSR is a

stream cipher stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream ( keystream). In a stream cipher, each plaintext digit is encrypted one at a time with the corresponding digit of the keystream ...

developed by Thierry Berger, François Arnault, and Cédric Lauradoux. The core of the cipher is a Feedback with Carry Shift Register (FCSR) automaton, which is similar to a

LFSR In computing, a linear-feedback shift register (LFSR) is a shift register whose input bit is a linear function of its previous state. The most commonly used linear function of single bits is exclusive-or (XOR). Thus, an LFSR is most often a s ...

, but they perform operations with carries so their transition function is nonlinear. F-FCSR was one of the eight algorithms selected for the

eCRYPT ECRYPT (European Network of Excellence in Cryptology) was a 4-year European research initiative launched on 1 February 2004 with the stated objective of promoting the collaboration of European researchers in information security, and especially in ...

network's

eSTREAM eSTREAM is a project to "identify new stream ciphers suitable for widespread adoption", organised by the EU ECRYPT network. It was set up as a result of the failure of all six stream ciphers submitted to the NESSIE project. The call for primi ...

Portfolio, but it was later removed because further analysis showed weaknesses.

References

Broken stream ciphers {{crypto-stub