KN-Cipher
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| Designer(s): | Kaisa Nyberg and Lars Knudsen |
|---|---|
| First published: | 1995 |
| Key size(s): | 198 bits |
| Block size(s): | 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. | |
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 didn't specify any key schedule for the cipher; they state, "All round keys should be independent, therefore we need at least 198 key bits."
- K. Nyberg, L.R. Knudsen (1995). "Provable Security Against a Differential Attack" (PDF/PostScript). Journal of Cryptology 8 (1). Retrieved on 2007-01-23.
- T. Jakobsen, L.R. Knudsen (1997-01). "The Interpolation Attack on Block Ciphers" (PDF/PostScript). 4th International Workshop on Fast Software Encryption (FSE '97): 28-40, Haifa: Springer-Verlag. Retrieved on 2007-01-23.