This page uses content from Wikipedia and is licensed under CC BY-SA.

Zodiac (cipher)

Designers Chang-Hyi Lee
First published 2000
Derived from SAFER, SHARK
Related to Xenon
Cipher detail
Key sizes 128, 192, or 256 bits
Block sizes 128 bits
Structure Feistel network
Rounds 16
Best public cryptanalysis
Impossible differential cryptanalysis recovers 128-bit key in 2119 encryptions

In cryptography, Zodiac is a block cipher designed in 2000 by Chang-Hyi Lee for the Korean firm SoftForum.

Zodiac uses a 16-round Feistel network structure with key whitening. The round function uses only XORs and S-box lookups. There are two 8×8-bit S-boxes: one based on the discrete exponentiation 45x as in SAFER, the other using the multiplicative inverse in the finite field GF(28), as introduced by SHARK.

Zodiac is theoretically vulnerable to impossible differential cryptanalysis, which can recover a 128-bit key in 2119 encryptions.


Further reading

  • HONG D, SUNG J, MORIAI S, LEE S & LIM J (2002). "Cryptography and Information Security. Impossible Differential Cryptanalysis of Zodiac". IEICE Trans Fundam Electron Commun Comput Sci. E85-A (1): 38–43. 
  • Wen Ji & Lei Hu (2008). "Square Attack on Reduced-Round Zodiac Cipher". Information Security Practice and Experience. Springer. pp. 377–391. doi:10.1007/978-3-540-79104-1_27. ISBN 978-3-540-79103-4.