cryptographic hash project

Background Information

A hash function takes binary data, called the message, and produces a condensed representation, called the message digest. A cryptographic hash function is a hash function that is designed to achieve certain security properties. The Federal Information Processing Standard 180-2, Secure Hash Standard, specifies algorithms for computing five cryptographic hash functions — SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512. FIPS 180-2 was issued in August, 2002, superseding FIPS 180-1.

In recent years, several of the non-NIST approved cryptographic hash functions have been successfully attacked, and serious attacks have been published against SHA-1. In response, NIST held two public workshops (see menu at left) to assess the status of its approved hash functions and to solicit public input on its cryptographic hash function policy and standard. As a result of these workshops, NIST has decided to develop one or more additional hash functions through a public competition, similar to the development process of the Advanced Encryption Standard (AES). NIST has proposed a tentative timeline for the competition, and also published a policy on the use of the current hash functions.

NIST issued draft minimum acceptability requirements, submission requirements, and evaluation criteria for candidate hash algorithms in January, 2007 [Federal Register Notice (January 23, 2007)] for public comments; the comment period ended on April 27, 2007. Based on the public feedback, NIST has revised the requirements and evaluation criteria and issued a Call for a New Cryptographic Hash Algorithm (SHA-3) Family on November 2, 2007 [Federal Register Notice (November 2, 2007)] to launch the hash algorithm competition. Details of the competition are available at www.nist.gov/hash-competition .