# wangyi-fudan/wyhash

The FASTEST QUALITY hash function, random number generators (PRNG) and hash map.

Repository: https://github.com/wangyi-fudan/wyhash
Canonical: https://ross.abutalabs.com/products/wyhash
Language: C
License: Unlicense
License Family: permissive
Topics: hash, fast, simple, random-number-generators, c, hashmap, bloom-filter
Last push: 2026-03-23T06:23:49+00:00

## Health v2 (maintenance only)
Score: 56/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 73, release rhythm 8, longevity 100
- inputs: {"age_days": 2737, "days_push": 163, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1146, forks 75 (observed 2026-08-28T04:03:45.865006+00:00)

## What it is
wyhash is a fast, high-quality 64-bit non-cryptographic hash function with accompanying PRNG (wyrand/w1rand) and hash map, written in portable C. It is the default hash in Zig, V, Nim, and Go's runtime, and has evolved into rapidhash.

## Use cases
- fastest 64-bit hash function for hash tables
- seeded PRNG that passes BigCrush and PractRand
- hashing for bloom filters
- default hash for language runtimes
- portable hashing across 32/64-bit and endiannesses

## When to choose
- you need maximum hashing speed on 64-bit machines, especially for short keys
- you want a tiny, simple, portable hash implementation
- you need a salted hash resistant to intended collision attacks

## When to avoid
- you need cryptographic security or full 64-bit collision resistance (it offers ~62 bits)
- you need a PRNG that passes PractRand on very long datasets (32TB+)
- you want the actively evolved successor - consider rapidhash instead

## Facets
- artifact type: library
- maturity: maintenance
- function: cryptography, developer-tools
- domain: performance, developer-tools
- platform: cross-platform, c, cpp
- tags: hash-function, prng, non-cryptographic-hash, hashmap, bloom-filter, smhasher, algorithms

## Member repositories
- wangyi-fudan/wyhash (main) score 56

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:45.865006+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 2026-08-30T06:34:13.472405+00:00, confidence not recorded.
  - readme: https://github.com/wangyi-fudan/wyhash (fetched 2026-08-28T04:03:45.865006+00:00, sha 37db4c97035c)
- Data as of 2026-08-30T08:39:29.467469+00:00.