JS implementation of Havok-N, a modified version of Fletcher & Adler checksums plus an optional iterative hash function.
npm install havok-nA modified version of Fletcher & Adler checksums plus an optional iterative hash function, by Lucy Havok.
Fletcher's Checksum algorithm is way overengineered. Adler had the right idea
with many of the tweaks he made to simplify and solidify the algorithm.
However, I liked the idea of having a user-defined arbitrary checksum bitdepth,
but also make sure that the modulo is always prime so as to reduce checksum
collision.
| Fletcher | Adler | Havok | |
|---|---|---|---|
| Word Size | 8b | 16b | 32b | 8b | 8b |
| Bits | 16 | 32 | 64 | 32 | arbitrary |
| Modulo | 28 | 216 | 232 | 65,521 | nearest prime under 2Bits |
| Shift | 8 | 16 | 32 | 16 | Bits/2 |
| Iterative Hash | no | no | optional, arbitrary |
``sh`
npm install havok-n
`js
const HavokN = require('havok-n');
var data = "Toast"; // This is the data you want a sum of. Can be of any type.
var bitdepth = 16; // This is sort of like the length of the checksum, but it's not directly proportionate. If you wanted to pretend this is Adler-32, you would put 32 here. Should be an integer.
var iterations = 0; // Optional. This is the number of iterations over the iterative hash function (defaults to 0).
HavokN(data, bitdepth, iterations);
``
Havok-N is part of the EmojiHash
project at Peepee Party, of which I am the creator,
maintainer, and current sole contributor. The upstream version of havokn.js can
be seen at https://fossil.peepee.party/emojihash/file?name=js/havokn.js.