# cmuratori/meow_hash

Official version of the Meow hash, an extremely fast level 1 hash

Repository: https://github.com/cmuratori/meow_hash
Canonical: https://ross.abutalabs.com/products/meow_hash
Homepage: https://mollyrocket.com/meowhash
Language: C++
License: Zlib
License Family: permissive
Topics: hash, hashing-algorithm, hash-functions
Last push: 2022-07-31T23:06:23+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 2875, "days_push": 1494, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1829, forks 65 (observed 2026-08-28T04:05:41.703273+00:00)

## What it is
Meow Hash is an extremely fast non-cryptographic hash function taking a 128-byte seed and producing 128-bit output, implemented in C/C++ using x64 AES-NI instructions. It is classified as level 1, meaning it is unsuitable for MACs or adversarial hash-table scenarios but excellent for non-adversarial bulk hashing.

## Use cases
- fast non-cryptographic hashing of large buffers
- hashing data for checksums in non-adversarial settings
- high-performance hashing for content-addressed storage
- benchmarking hash function speed against xxHash and similar
- hashing where AES-NI hardware acceleration is available

## When to choose
- you need maximum bulk hashing throughput on x64 CPUs with AES-NI
- your hashing workload is non-adversarial and collision attacks are not a concern
- you want a 128-bit output hash with a large 128-byte seed

## When to avoid
- you need a hash for message authentication codes - use SipHash instead
- hash tables may face collision-induced denial-of-service attacks from untrusted input
- you need a platform without x64 AES-NI support or an officially vetted port

## Facets
- artifact type: library
- maturity: maintenance
- function: cryptography, security
- domain: performance, developer-tools
- platform: cpp, windows, cross-platform
- tags: non-cryptographic-hash, aes-ni, hash-function, simd, algorithms, linux

## Member repositories
- cmuratori/meow_hash (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:41.703273+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:19:21.742742+00:00, confidence not recorded.
  - readme: https://github.com/cmuratori/meow_hash (fetched 2026-08-28T04:05:41.703273+00:00, sha ab0b919355d6)
  - homepage: https://mollyrocket.com/meowhash (fetched 2026-08-29T10:58:11.692006+00:00, sha e276238e1b5b)
- Data as of 2026-08-30T08:39:29.467469+00:00.