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Nimbus (cipher)

Nimbus
General
DesignersAlexis Machado
First published2000
Cipher detail
Key sizes128 bits
Block sizes64 bits
Rounds5
Best public cryptanalysis
Differential cryptanalysis can break Nimbus with 256 chosen plaintexts.

In cryptography, Nimbus is a block cipher invented by Alexis Machado in 2000. It was submitted to the NESSIE project, but was not selected.

The algorithm uses a 128-bit key. It operates on blocks of 64 bits and consists of 5 rounds of encryption. The round function is exceedingly simple. In each round the block is XORed with a subkey, the order of its bits is reversed, and then it is multiplied mod 264 by another subkey, which is forced to be odd.[1]

Nimbus was broken by Vladimir Furman; he found a differential attack using only 256 chosen plaintexts.[2]

References

  1. ^ Murphy, Sean; White, Juliette (2001-09-23). "Security Evaluation of NESSIE First Phase: 2.4.6 Nimbus" (PDF). p. 22. Retrieved 2018-09-13.
  2. ^ Eli Biham, Vladimir Furman (2000-11-29). "Differential Cryptanalysis of Nimbus" (PDF/PostScript). ISBN 978-3-540-45473-1. Retrieved 2018-09-13.