LOKI89
In cryptography, LOKI89 and LOKI91 are block ciphers designed as possible replacements for the Data Encryption Standard (DES). The ciphers were developed based on a body of work analysing DES, and are very similar to DES in structure. The LOKI algorithms were named for Loki, the god of mischief in Norse mythology.
LOKI89
LOKI89 was first published in 1990, then named just "LOKI", by Austrialian cryptographers Lawrie Brown, Josef Pieprzyk and Jennifer Seberry. LOKI89 was submitted to the European RIPE project for evaluation, but was not selected.
The cipher uses a 64-bit block and a 64-bit key. Like DES, it is a 16-round Feistel cipher and has a similar general structure, but differs in the choice of the particular S-boxes, the "P-permutation", and the "Expansion permutation".
LOKI91
LOKI 91 was designed in response to the attacks on LOKI89 (Brown et. al., 1991). The changes included removing the initial and final key whitening, a new S-box, and small alterations to the key schedule.
See also
References
- L. Brown, Josef Pieprzyk and Jennifer Seberry, " LOKI - A Cryptographic Primitive for Authentication and Secrecy Applications", Technical Report CS1/90, 18 Jan 1990. Also published in Advances in Cryptology - Auscrypt'90, Lecture Notes in Computer Science, vol 453, pp229-236, J Seberry, J Pieprzyk (eds), Springer-Verlag, 1990.
- L. Brown, M Kwan, J Pieprzyk, J Seberry, " Improving Resistance to Differential Cryptanalysis and the Redesign of LOKI", Technical Report CS19/91, July 1991. Also published in Advances in Cryptology - Asiacrypt'91", Lecture Notes in Computer Science, vol 739, pp 36-50, H Imai et al (eds), Springer-Verlag, 1993.
- Eli Biham, Adi Shamir: Differential Cryptanalysis of Snefru, Khafre, REDOC-II, LOKI and Lucifer. CRYPTO 1991: 156-171
- Lars R. Knudsen: Cryptanalysis of LOKI. ASIACRYPT 1991: 22-35
- Lars R. Knudsen: Cryptanalysis of LOKI91. ASIACRYPT 1992: 196-208
- Lars R. Knudsen: New Potentially 'Weak' Keys for DES and LOKI (Extended Abstract). EUROCRYPT 1994:
- Lars Knudsen, M.J.B. Robshaw, "Non-linear Approximations in Linear Cryptanalysis", in Advances in Cryptology - Eurocrypt'96, Lecture Notes in Computer Science, Vol 1070, Springer-Verlag, pp 224-236, 1996.
- Kouichi Sakurai, Souichi Furuya: Improving Linear Cryptanalysis of LOKI91 by Probabilistic Counting Method. Fast Software Encryption 1997: 114-133
- Toshio Tokita, Tohru Sorimachi, Mitsuru Matsui: Linear Cryptanalysis of LOKI and s2DES. ASIACRYPT 1994: 293-303
