KN-Cipher

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KN-Cipher
General
Designers Kaisa Nyberg and Lars Knudsen
First published 1995
Cipher detail
Key sizes 198 bits
Block sizes 64 bits
Structure Feistel network
Rounds 6
Best public cryptanalysis
Jakobsen & Knudsen's higher order differential cryptanalysis breaks KN-Cipher with only 512 chosen plaintexts and 241 running time, or with 32 chosen plaintexts and 270 running time.[1]

In cryptography, KN-Cipher is a block cipher created by Kaisa Nyberg and Lars Knudsen in 1995. One of the first ciphers designed to be provably secure against ordinary differential cryptanalysis, KN-Cipher was later broken using higher order differential cryptanalysis.

Presented as "a prototype...compatible with DES", the algorithm has a 64-bit block size and a 6-round Feistel network structure. The round function is based on the cube operation in the finite field GF(233).

The designers did not specify any key schedule for the cipher; they state, "All round keys should be independent, therefore we need at least 198 key bits."[2]

Cryptanalysis[edit]

Jakobsen & Knudsen's higher order differential cryptanalysis breaks KN-Cipher with only 512 chosen plaintexts and 241 running time, or with 32 chosen plaintexts and 270 running time.[1]

References[edit]

  1. ^ a b T. Jakobsen, L.R. Knudsen (January 1997). The Interpolation Attack on Block Ciphers (PDF/POSTSCRIPT). 4th International Workshop on Fast Software Encryption (FSE '97). Haifa: Springer-Verlag. pp. 28–40. Retrieved 23 January 2007. 
  2. ^ K. Nyberg, L.R. Knudsen (1995). "Provable Security Against a Differential Attack" (PDF/POSTSCRIPT). Journal of Cryptology 8 (1): 27–37. doi:10.1007/bf00204800. ISSN 0933-2790. Retrieved 23 January 2007.