NOEKEON ˈnuːki.ɒn is a family of two block cipher

Block cipher

In cryptography, a block cipher is a symmetric key cipher operating on fixed-length groups of bits, called blocks, with an unvarying transformation. A block cipher encryption algorithm might take a 128-bit block of plaintext as input, and output a corresponding 128-bit block of ciphertext...

s designed by Joan Daemen

Joan Daemen

Joan Daemen |Limburg]], Belgium) is a Belgian cryptographer and one of the designers of Rijndael, the Advanced Encryption Standard , together with Vincent Rijmen. He has also designed or co-designed the MMB, Square, SHARK, NOEKEON, 3-Way, and BaseKing block ciphers...

, Michaël Peeters, Gilles Van Assche and Vincent Rijmen

Vincent Rijmen

Vincent Rijmen is a Belgian cryptographer and one of the two designers of the Rijndael, the Advanced Encryption Standard. Rijmen is also the co-designer of the WHIRLPOOL cryptographic hash function, and the block ciphers Anubis, KHAZAD, Square, NOEKEON and SHARK.In 1993, Rijmen obtained a degree...

 and submitted to the NESSIE

NESSIE

NESSIE was a European research project funded from 2000–2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Government-sponsored CRYPTREC project, but with notable differences from both...

 project in September 2000. The two ciphers are "direct mode" NOEKEON, to be used for maximum efficiency where related-key attack

Related-key attack

In cryptography, a related-key attack is any form of cryptanalysis where the attacker can observe the operation of a cipher under several different keys whose values are initially unknown, but where some mathematical relationship connecting the keys is known to the attacker...

s are not possible, and "indirect mode" NOEKEON where they are.

NOEKEON has a 128-bit block and key size. Each round of NOEKEON employs a sequence of self-inverse transformations which can be implemented easily in hardware or software, even where differential power analysis is a concern. It is designed according to a variant of the wide-trail strategy.

Cryptanalysis by Lars Knudsen

Lars Knudsen

Lars Ramkilde Knudsen is a Danish researcher in cryptography, particularly interested in the design and analysis of block ciphers, hash functions and message authentication codes .-Academic:...

 and Håvard Raddum in April 2001 showed that "indirect mode" NOEKEON was still vulnerable to certain peculiar kinds of related-key cryptanalysis, and showed weaknesses in NOEKEON-variant ciphers which cast doubt on the design strategy behind NOEKEON and thus on its security. As a result it was not a NESSIE selected algorithm.

The authors of NOEKEON contend ("On NOEKEON, no!") that the related-key attacks required to break "indirect mode" NOEKEON are not a practical concern, and that it is as a result of deliberate design that NOEKEON is not vulnerable to the attacks that break the variant ciphers; they assert that NOEKEON is still a good and useful cipher.

External links

• The NOEKEON Page
• Lars Knudsen
  Lars Knudsen
  Lars Ramkilde Knudsen is a Danish researcher in cryptography, particularly interested in the design and analysis of block ciphers, hash functions and message authentication codes .-Academic:...
  
   and Håvard Raddum On NOEKEON