---
title: "FNV-1a (64-bit)"
description: "FNV-1a in 64 bits. XOR a byte and multiply by a prime and repeat. For tables and fingerprints"
canonical_url: "https://hashes.agntn.dev/algorithms/fnv1a"
---
# FNV-1a (64-bit)

> FNV-1a in 64 bits. XOR a byte and multiply by a prime and repeat. For tables and fingerprints

<algorithm-facts name="fnv1a">



</algorithm-facts>

The simplest hash here: start from the offset basis, XOR in a byte, multiply by the FNV prime, repeat. Tiny, fast on short keys, and trivially attackable.

```ts
create("fnv1a").hash("").digest; // "cbf29ce484222325", the offset basis itself
create("fnv1a").hash("a").digest; // "af63dc4c8601ec8c"
```

64-bit only. The [custom algorithms](https://hashes.agntn.dev/guide/custom) page builds the 32-bit one in fifteen lines, if that's what your format wants.


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