NIST names Keccak hashing algorithm as SHA-3
The United States National Institute of Standards and Technology (NIST) has announced the winner of its competition to select a cryptographic hash algorithm to bear the name SHA-3. The five-year competition attracted 64 entries in total with the winner being the Keccak (pronounced "catch-ack" according to NIST, and "ketchak" according to its creators) algorithm created by Guido Bertoni, Joan Daemen, Gilles Van Assche and Michaël Peeters. The competition was created in 2007 when NIST had reasons to suspect that the current SHA-2 algorithm might be threatened.
Keccak was selected for its ability to run on a large variety of computing hardware and because, in tests carried out by NIST and independent reviewers, it was the fastest algorithm when implemented in hardware.
NIST also highlighted the fact that, unlike all other members of the Secure Hash Algorithm (SHA) family and the related MD4 and MD5 algorithms, Keccak does not use a Merkle-Damgard approach to creating hashes. Instead, Keccak uses a design called a "sponge function" by its creators. This, NIST computer security expert Tim Polk said, is desirable as it makes it unlikely that an attack that would defeat SHA-2 could also defeat SHA-3. The conceptual differences between the two approaches provide an added insurance against future vulnerabilities and would enable NIST to fall back to the other family of hashing functions should it be discovered that any one approach is vulnerable to attack.
SHA-2 is currently still considered secure and suitable for general use by NIST, but having a second algorithm gives "security designers more flexibility," Polk said. The ability to be run very efficiently in hardware implementation also makes SHA-3 interesting for embedded and mobile applications.
Security expert Bruce Schneier, a member of the Skein algorithm team that lost out to Keccak in the competition, called the winner "a fine hash function" and says he has "absolutely no reservations about its security." He also congratulated NIST on having run a very professional competition.
- Cryptographic Sponge Functions, a paper by the Keccak development team.