| 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
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
References
- 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.
- 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. S2CID 11867695. Retrieved 23 January 2007.