Changes in Federal Information Processing Standard (FIPS) 180-4, Secure Hash Standard

Abstract

This article describes the changes between Federal Information Processing Standards FIPS 180-3 and FIPS 180-4. FIPS 180-4 specifies two new secure cryptographic hash algorithms: secure hashing algorithms SHA-512/224 and SHA-512/256; it also includes a method for determining initial value(s) for any future SHA-512-based hash algorithm(s). FIPS 180-4 also removes a requirement for the execution of the message length encoding operation.

Keywords:

• FIPS 180
• hash algorithm
• hash function
• SHA-512
• SHA-512/224
• SHA-512/256

Notes

¹As many readers of Cryptologia will know, on 2 October 2012, NIST announced the winner of its competition to select a new cryptographic hash algorithm, which will be known as SHA-3. However, the announcement also stated that “SHA-2 has held up well and NIST considers SHA-2 to be secure and suitable for general use.” (See http://www.nist.gov/itl/csd/sha-100212 for details.) Therefore, although we expect NIST to release a new version of FIPS 180 soon, the algorithms discussed in this article will very likely continue to be approved standards for the foreseeable future. We at Cryptologia plan to have a report on the new standard as soon as it is released. In the meantime, we are very excited to have a paper in the works by the designers of Keccak, the winner of the SHA-3 competition, which we hope to bring you in an upcoming issue.

This article not subject to United States copyright law.

Additional information

Notes on contributors

Quynh Dang

Quynh Dang is a computer scientist at National Institute of Standards and Technology. His work in the last many years has been in the fields of cryptographic algorithms and network security protocols.