Hawkynt

XCBC-MAC

Extended Cipher Block Chaining Message Authentication Code. Uses three derived keys with AES for cryptographic authentication.

Properties

Property	Value
Category	Message Authentication
Sub-category	XCBC
Security status	🛡️ Secure
Complexity	Intermediate
Inventor	John Black, Phillip Rogaway
Year	2000
Origin	🇺🇸 United States
Source	algorithms/mac/xcbc.js

Parameters

Parameter	Supported values
MAC sizes	16 bytes (128 bits)

Capabilities

Flag	Value
NeedsKey	Yes

Security

Status: 🛡️ Secure

No vulnerabilities are recorded for this implementation.

Documentation

• RFC 3566 - The AES-XCBC-MAC-96 Algorithm
• Black and Rogaway - CBC MACs for Arbitrary-Length Messages

References

• LibTomCrypt XCBC Implementation
• RFC 3566 Full Specification

Test vectors

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

Vector 1 — LibTomCrypt Test Vector 1 - Empty Message

Field	Value
key	000102030405060708090a0b0c0d0e0f
input	(empty)
expected	75f0251d528ac01c4573dfd584d79f29

Vector 2 — LibTomCrypt Test Vector 2 - 3 bytes

Field	Value
key	000102030405060708090a0b0c0d0e0f
input	000102
expected	5b376580ae2f19afe7219ceef172756f

Vector 3 — LibTomCrypt Test Vector 3 - Single Block

Field	Value
key	000102030405060708090a0b0c0d0e0f
input	000102030405060708090a0b0c0d0e0f
expected	d2a246fa349b68a79998a4394ff7a263

Vector 4 — LibTomCrypt Test Vector 4 - Two Blocks

Field	Value
key	000102030405060708090a0b0c0d0e0f
input	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
expected	f54f0ec8d2b9f3d36807734bd5283fd4

Vector 5 — LibTomCrypt Test Vector 5 - 34 bytes

Field	Value
key	000102030405060708090a0b0c0d0e0f
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 2021
expected	becbb3bccdb518a30677d5481fb6b4d8

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