FORK-256 is a hash algorithm designed in response to security issues discovered in the earlier SHA-1 and MD5 algorithms. After substantial cryptanalysis, the algorithm is considered broken.
Contents
Background
In 2005, Xiaoyun Wang announced an order-
Algorithm and Analysis
FORK-256 was introduced at the 2005 NIST Hash workshop and published the following year. FORK-256 uses 512-bit blocks and implements preset constants that change after each repetition. Each block is hashed into a 256-bit block through four branches that divides each 512 block into sixteen 32-bit words that are further encrypted and rearranged.
The initial algorithm garnered significant cryptanalysis, summarized in (Saarinen 2007). Matusiewicz et al. (2006) discovered a collision attack with complexity of
In response to these attacks, Hong and his team proposed an improved version of FORK-256. Markku-Juhani Saarinen derived a
Deployment
FORK-256 was added to the Botan cryptographic library after its introduction. Botan developer Jack Lloyd removed the algorithm in 2010 after concluding the hash suffered from several weaknesses and had never become widely used.