Hawkynt

SP800-56C

NIST SP 800-56C Two-Step Key Derivation Function. Extract-and-Expand pattern using HMAC for deriving cryptographic keys from shared secrets, similar to HKDF but following NIST standardized specification.

Properties

Property	Value
Category	Key Derivation Functions
Sub-category	Two-Step KDF (Extract-and-Expand)
Security status	🛡️ Secure
Complexity	Intermediate
Inventor	NIST
Year	2018
Origin	🇺🇸 United States
Source	algorithms/kdf/sp800-56c.js

Parameters

Parameter	Supported values
Key derivation sizes	1 byte (8 bits) to 16320 bytes (130560 bits)

Capabilities

Flag	Value
SaltRequired	Yes
NeedsKey	Yes

Security

Status: 🛡️ Secure

No vulnerabilities are recorded for this implementation.

Documentation

• NIST SP 800-56C Revision 2 - Recommendation for Key-Derivation Methods in Key-Establishment Schemes
• RFC 5869 - HMAC-based Extract-and-Expand Key Derivation Function (HKDF)

References

• PyCryptodome SP800-56C Implementation
• Botan SP800-56C Test Vectors

Test vectors

3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — SP 800-56C - HMAC-SHA1 Test Vector 1 (2 bytes)

Field	Value
salt	97ca00eac481e8b3556a
label	ae8cf2e46773a68098ea53b3
outputLength	2
hashAlgorithm	SHA-1
input	52f4676023946c7307b5e8148d97f312623a6e88
expected	1bcd

Vector 2 — SP 800-56C - HMAC-SHA1 Test Vector 2 (4 bytes)

Field	Value
salt	76b026053771b88e4e833962a10083835a33ddd9
label	f2d44c1b59d725ad7c662ca6
outputLength	4
hashAlgorithm	SHA-1
input	eecb51e6d59a6fe688fb591799891d9211745a13
expected	bc3d9b22

Vector 3 — SP 800-56C - HMAC-SHA256 Test Vector 1 (3 bytes)

Field	Value
salt	28e12e410d501368b3e8
label	94d91d500177efafdc93e8b6
outputLength	3
hashAlgorithm	SHA-256
input	b3dad1f46a18430ea0c8fbe2172922a5a42c47af40046db24d38cb11eff4ce44
expected	d4c1fb

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