| General | |
|---|---|
| Designers | Vincent Rijmen and Paulo S. L. M. Barreto |
| First published | 2000 |
| Derived from | SHARK |
| Cipher detail | |
| Key sizes | 128 bits |
| Block sizes | 64 bits |
| Structure | Substitution–permutation network |
| Rounds | 8 |
| Best publiccryptanalysis | |
| No attack better than on the first five rounds is known. | |
Incryptography,KHAZAD is ablock cipher designed byPaulo S. L. M. Barreto together withVincent Rijmen, one of the designers of theAdvanced Encryption Standard (Rijndael). KHAZAD is named afterKhazad-dûm, the fictionaldwarven realm in the writings ofJ. R. R. Tolkien (see alsoKhazad). KHAZAD was presented at the firstNESSIE workshop in 2000, and, after some small changes, was selected as a finalist in the project.
KHAZAD has an eight-roundsubstitution–permutation network structure similar to that ofSHARK, a forerunner to Rijndael. The design is classed as a "legacy-level" algorithm, with a 64-bitblock size (in common with olderciphers such asDES andIDEA) and a 128-bitkey. KHAZAD makes heavy use ofinvolutions as subcomponents; this minimises the difference between the algorithms forencryption anddecryption.
The authors have stated that,"KHAZAD is not (and will never be)patented. It may be used free of charge for any purpose."
Frédéric Muller has discovered an attack which can break five of KHAZAD's eight rounds. No attacks better than this are known as of August 2009.
