cryptography Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or ''-logy, -logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of Adversary (cryptography), ...

, KHAZAD is a

block cipher In cryptography, a block cipher is a deterministic algorithm that operates on fixed-length groups of bits, called ''blocks''. Block ciphers are the elementary building blocks of many cryptographic protocols. They are ubiquitous in the storage a ...

Paulo S. L. M. Barreto Paulo Licciardi Barreto (born Paulo Sérgio Licciardi Messeder Barreto on November 19, 1965) is a Brazilian_Americans, Brazilian-American cryptographer and one of the designers of the Whirlpool (algorithm), Whirlpool cryptographic hash function, ...

together with

Vincent Rijmen Vincent Rijmen (; born 16 October 1970) is a Belgium, 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 ...

, one of the designers of the

Advanced Encryption Standard The Advanced Encryption Standard (AES), also known by its original name Rijndael (), is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001. AES is a variant ...

(

Rijndael The Advanced Encryption Standard (AES), also known by its original name Rijndael (), is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001. AES is a variant ...

). KHAZAD is named after

Khazad-dûm In the fictional history of the world by J. R. R. Tolkien, Moria, also named Khazad-dûm, is an ancient subterranean complex in Middle-earth, comprising a vast labyrinthine network of tunnels, chambers, mines, and halls under the Misty Mountain ...

, the fictional dwarven realm in the writings of

J. R. R. Tolkien John Ronald Reuel Tolkien (, 3 January 1892 – 2 September 1973) was an English writer and philologist. He was the author of the high fantasy works ''The Hobbit'' and ''The Lord of the Rings''. From 1925 to 1945, Tolkien was the Rawlinson ...

(see also Khazad). KHAZAD was presented at the first

NESSIE NESSIE (New European Schemes for Signatures, Integrity and Encryption) was a European research project funded from 2000 to 2003 to identify secure cryptographic primitives. The project was comparable to the NIST AES process and the Japanese Go ...

workshop in 2000, and, after some small changes, was selected as a finalist in the project. KHAZAD has an eight-round

substitution–permutation network In cryptography, an SP-network, or substitution–permutation network (SPN), is a series of linked mathematical operations used in block cipher algorithms such as AES (Rijndael), 3-Way, Kalyna, Kuznyechik, PRESENT, SAFER, SHARK, and Square. ...

structure similar to that of

SHARK Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...

, a forerunner to Rijndael. The design is classed as a "''legacy-level''" algorithm, with a 64-bit block size (in common with older

cipher In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. An alternative, less common term is ''encipherment''. To encipher or encode i ...

s such as DES and

IDEA In philosophy and in common usage, an idea (from the Greek word: ἰδέα (idea), meaning 'a form, or a pattern') is the results of thought. Also in philosophy, ideas can also be mental representational images of some object. Many philosophe ...

) and a 128-bit key. KHAZAD makes heavy use of

involution Involution may refer to: Mathematics * Involution (mathematics), a function that is its own inverse * Involution algebra, a *-algebra: a type of algebraic structure * Involute, a construction in the differential geometry of curves * Exponentiati ...

s as subcomponents; this minimises the difference between the algorithms for

encryption In Cryptography law, cryptography, encryption (more specifically, Code, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the inf ...

and

decryption In cryptography, encryption (more specifically, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the information, known as plai ...

. The authors have stated that, ''"KHAZAD is not (and will never be)

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

ed. 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.

References

* * *

External links

* {{Cryptography navbox , block Block ciphers Free ciphers