Q_(cipher)

Q (cipher)

Q (cipher)

Block cipher

This article is about the block cipher. For other uses, see Q (disambiguation).

In cryptography, Q is a block cipher invented by Leslie McBride. It was submitted to the NESSIE project, but was not selected.

Quick Facts General, Designers ...

The algorithm uses a key size of 128, 192, or 256 bits. It operates on blocks of 128 bits using a substitution–permutation network structure. There are 8 rounds for a 128-bit key and 9 rounds for a longer key. Q uses S-boxes adapted from Rijndael (also known as AES) and Serpent. It combines the nonlinear operations from these ciphers, but leaves out all the linear transformations except the permutation.[2] Q also uses a constant derived from the golden ratio as a source of "nothing up my sleeve numbers".

Q is vulnerable to linear cryptanalysis; Keliher, Meijer, and Tavares have an attack that succeeds with 98.4% probability using 297 known plaintexts.[1]

References

  1. [1]
    L. Keliher, H. Meijer, and S. Tavares (12 September 2001). High probability linear hulls in Q. Proceedings of Second Open NESSIE Workshop. Surrey, England. Retrieved 2018-09-13.{{cite conference}}: CS1 maint: multiple names: authors list (link)
  2. [2]
    Eli Biham, Vladimir Furman, Michal Misztal, Vincent Rijmen (11 February 2001). Differential Cryptanalysis of Q. 8th International Workshop on Fast Software Encryption (FSE 2001). Yokohama: Springer-Verlag. pp. 174–186. doi:10.1007/3-540-45473-X_15.{{cite conference}}: CS1 maint: multiple names: authors list (link)
Share this article:

This article uses material from the Wikipedia article Q_(cipher), and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.