1 December 2003
Source: http://csrc.nist.gov/publications/fips/fips180-2/FIPS180-2_changenotice.pdf

FIPS 180-2, SECURE HASH STANDARD

CHANGE NOTICE 1

U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

Gaithersburg, MD 20899
 

DATE OF CHANGE: year month day

Federal Information Processing Standard (FIPS) 180-2, Secure Hash Standard, specifies four secure hash functions - SHA-1, SHA-256, SHA-384, and SHA-512 - for computing a condensed representation of electronic data (a message). When a message of any length < 2⁶⁴ bits (for SHA-1 and SHA-256) or < 2¹²⁸ bits (for SHA-384 and SHA-512) is input to a hash function, the result is an output called a message digest. The message digests  range in length from 160 to 512 bits, depending on the hash function.

This change notice specifies an additional hash function, SHA-224. Figure 1 of this Standard (see Section 1) specifies the basic properties of the SHA-1, SHA-256, SHA-384 and SHA-512 hash functions. The following table specifies those properties for SHA-224.

Questions regarding this change notice may be directed to Elaine Barker (Email: ebarker@nist.gov, Phone: 301-975-2911).

1 SHA-224 Specification

SHA-224 may be used to hash a message, M, having a length of l bits, where 0 < l < 2⁶⁴ . The function is defined in the exact same manner as SHA-256 (Section 6.2), with the following two exceptions:

1. For SHA-224, the initial hash value, H⁽⁰⁾, shall consist of the following eight (8) 32-bit words:

H₀⁽⁰⁾ = c1059ed8

H₁⁽⁰⁾ = 367cd507

H₂⁽⁰⁾ = 3070dd17

H₃⁽⁰⁾ = f70e5939

H₄⁽⁰⁾ = ffc00b31

H₅⁽⁰⁾ = 68581511

H₆⁽⁰⁾ = 64f98fa7

H₇⁽⁰⁾ = befa4fa4

2. The 224-bit message digest is obtained by truncating the final hash value, H^(N), to its left- most 224 bits:

H₀^(N) || H₁^{(N) ||} H₂^{(N) ||} H₃^{(N) ||} H₄^(N) || H₅^{(N) ||} H₆^(N).

2 SHA-224 Examples

2.1 SHA-224 Example (One-Block Message)

[To be provided]

2.2 SHA-224 Example (Multi-Block Message)

[To be provided]

2.3 SHA-224 Example (Long Message)

[To be provided]