Hawkynt

HighwayHash

Google’s keyed hash function designed as a faster, stronger successor to SipHash. Absorbs 32-byte packets into a 256-bit state of multiply/permute/zipper-merge lanes and supports 64-, 128- and 256-bit output. Not a cryptographic hash, but designed to resist key recovery from observed outputs.

Properties

Property	Value
Category	Hash Functions
Sub-category	Keyed Hash Function
Security status	🎓 Educational Only
Complexity	Intermediate
Inventor	Jyrki Alakuijala, Bill Cox, Jan Wassenberg (Google)
Year	2016
Origin	🇺🇸 United States
Source	algorithms/hash/highway-hash.js

Parameters

Parameter	Supported values
Output sizes	8 bytes (64 bits); 16 bytes (128 bits); 32 bytes (256 bits)

Capabilities

Flag	Value
RequiresKey	Yes

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue	Description	Mitigation
Not a cryptographic hash	HighwayHash is not collision resistant against an adversary who knows the key, and is not a general-purpose message digest	Use only as a keyed hash/PRF with a secret key; use SHA-2 or SHA-3 where collision resistance is required

Documentation

• Google Research Paper
• GitHub Repository
• HighwayHash Specification

References

• Portable reference implementation (c/highwayhash.c)
• Official test vectors (highwayhash_test.cc)

Test vectors

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

Vector 1 — HighwayHash-64, size 0 (empty)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	(empty)
expected	536ec222de567a90

Vector 2 — HighwayHash-64, size 1

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	00
expected	78ddcdc7aa43ab7e

Vector 3 — HighwayHash-64, size 2

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	0001
expected	623db5b09a56d0b8

Vector 4 — HighwayHash-64, size 3

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	000102
expected	803d468aabef6b5c

Vector 5 — HighwayHash-64, size 4 (size_mod4 boundary)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	00010203
expected	da7e009368a405f2

Vector 6 — HighwayHash-64, size 7

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	00010203040506
expected	8294f53817ae024d

Vector 7 — HighwayHash-64, size 8

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	0001020304050607
expected	71315fe5085120e1

Vector 8 — HighwayHash-64, size 15

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	000102030405060708090a0b0c0d0e
expected	3bf349a4863f7940

Vector 9 — HighwayHash-64, size 16 (16-byte remainder branch boundary)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	000102030405060708090a0b0c0d0e0f
expected	32b87ef98934abcf

Vector 10 — HighwayHash-64, size 17

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	000102030405060708090a0b0c0d0e0f10
expected	e2c0c5c8d267fe19

Vector 11 — HighwayHash-64, size 31 (one below a full packet)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e
expected	685a03cf7c00c79f

Vector 12 — HighwayHash-64, size 32 (exactly one packet, no remainder)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
expected	fc80d5ecd964c9a0

Vector 13 — HighwayHash-64, size 33 (one over a full packet)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 20
expected	fc8131a03cf7902c

Vector 14 — HighwayHash-64, size 63

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e
expected	a03921bfe9eb8eab

Vector 15 — HighwayHash-64, size 64 (exactly two packets)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	8
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f
expected	ffa6d24c5d2c5475

Vector 16 — HighwayHash-128, size 0 (empty)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	16
input	(empty)
expected	c7fe8f9d8f26ed0f6f3e097f765e5633

Vector 17 — HighwayHash-128, size 1

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	16
input	00
expected	a8e7813689a8b0d6b4dc9cebf91d29dc

Vector 18 — HighwayHash-128, size 32 (exactly one packet)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	16
input	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
expected	aa4a43c166df8419b9e4b3f95819fc16

Vector 19 — HighwayHash-128, size 33

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	16
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 20
expected	6cc3c6e0af7816119d84a2e59db558f9

Vector 20 — HighwayHash-128, size 64

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	16
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f
expected	f2c4d498711fbb98c88f91de7105bce0

Vector 21 — HighwayHash-256, size 0 (empty)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	32
input	(empty)
expected	f574c8c22a4844dd1f35c713730146d9ff1487b9ccbeaeb3f41d75453123da41

Vector 22 — HighwayHash-256, size 1

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	32
input	00
expected	54825fe4bc41b9ed0fc6ca3def440de2474a32cb9b1b657284e475b24c627320

Vector 23 — HighwayHash-256, size 32 (exactly one packet)

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	32
input	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
expected	fec3a139908ce3bc8912c1a32663d542a9aefc64f79555e3995a47c96b3cb0c9

Vector 24 — HighwayHash-256, size 64

Field	Value
key	000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
outputSize	32
input	000102030405060708090a0b0c0d0e0f 101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f 303132333435363738393a3b3c3d3e3f
expected	7524c16affe6d890f2c1da6e192a421a02b08e1ffe65379ebecf51c3c4d7bdc1

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