Hawkynt

HMAC-SHA256

Hash-based Message Authentication Code using SHA-256 as defined in RFC 2104 and RFC 4231. Combines cryptographic hashing with a secret key to provide authentication and integrity verification.

Properties

Property	Value
Category	Message Authentication
Sub-category	HMAC
Security status	🛡️ Secure
Complexity	Beginner
Inventor	Mihir Bellare, Ran Canetti, Hugo Krawczyk
Year	1996
Origin	🇺🇸 United States
Source	algorithms/mac/hmac-sha256.js

Parameters

Parameter	Supported values
MAC sizes	1 byte (8 bits) to 64 bytes (512 bits)
Output sizes	1 byte (8 bits) to 32 bytes (256 bits)

Capabilities

Flag	Value
NeedsKey	Yes

Security

Status: 🛡️ Secure

No vulnerabilities are recorded for this implementation.

Documentation

• RFC 2104 - HMAC: Keyed-Hashing for Message Authentication
• RFC 4231 - Identifiers and Test Vectors for HMAC-SHA-224/256/384/512
• NIST FIPS 198-1 - The Keyed-Hash Message Authentication Code (HMAC)

References

• OpenSSL HMAC Implementation
• libsodium HMAC-SHA256
• Botan HMAC Implementation

Test vectors

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

Vector 1 — RFC 4231 Test Case 1 - ‘Hi There’

Field	Value
key	0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b
input	4869205468657265
expected	b0344c61d8db38535ca8afceaf0bf12b881dc200c9833da726e9376c2e32cff7

Vector 2 — RFC 4231 Test Case 2 - ‘what do ya want for nothing?’

Field	Value
key	4a656665
input	7768617420646f2079612077616e7420666f72206e6f7468696e673f
expected	5bdcc146bf60754e6a042426089575c75a003f089d2739839dec58b964ec3843

Vector 3 — RFC 4231 Test Case 3 - 50 bytes of 0xDD

Field	Value
key	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
input	dddddddddddddddddddddddddddddddd dddddddddddddddddddddddddddddddd dddddddddddddddddddddddddddddddd dddd
expected	773ea91e36800e46854db8ebd09181a72959098b3ef8c122d9635514ced565fe

Vector 4 — RFC 4231 Test Case 4 - 50 bytes of 0xCD

Field	Value
key	0102030405060708090a0b0c0d0e0f10111213141516171819
input	cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd cdcd
expected	82558a389a443c0ea4cc819899f2083a85f0faa3e578f8077a2e3ff46729665b

Vector 5 — RFC 4231 Test Case 6 - Key > Block Size

Field	Value
key	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaa
input	54657374205573696e67204c61726765 72205468616e20426c6f636b2d53697a 65204b6579202d2048617368204b6579 204669727374
expected	60e431591ee0b67f0d8a26aacbf5b77f8e0bc6213728c5140546040f0ee37f54

Vector 6 — RFC 4231 Test Case 7 - Large Key and Data

Field	Value
key	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaa
input	54686973206973206120746573742075 73696e672061206c6172676572207468 616e20626c6f636b2d73697a65206b65 7920616e642061206c61726765722074 68616e20626c6f636b2d73697a652064 6174612e20546865206b6579206e6565 647320746f2062652068617368656420 6265666f7265206265696e6720757365 642062792074686520484d414320616c 676f726974686d2e
expected	9b09ffa71b942fcb27635fbcd5b0e944bfdc63644f0713938a7f51535c3a35e2

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