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

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 values for any future SHA-512-based hash algorithms. FIPS 180-4 also removes a requirement for the execution of the message length encoding operation.