BLAKE2s implementation in JavaScript
====================================

BLAKE2 is a fast and secure cryptographic hash function.

This is a pure JavaScript public domain implementation of its BLAKE2s flavor
(currently without tree mode support).

* [BLAKE2s-js Demo](https://dchest.github.io/blake2s-js/)
* [BLAKE2 Website](https://blake2.net)

[![Build Status](https://travis-ci.org/dchest/blake2s-js.svg?branch=master)
](https://travis-ci.org/dchest/blake2s-js)

*Looking for BLAKE2b implementation? Check out:
<https://github.com/dcposch/blakejs>*

Installation
------------

Via NPM:

    $ npm install blake2s-js

Via Bower:

    $ bower install blake2s-js


or just download `blake2s.min.js`.


Usage
-----

### new BLAKE2s(digestLength, key)
### new BLAKE2s(digestLength, config)

Creates a new instance of BLAKE2s hash with the given length of digest (default
and maximum 32) and an optional secret key (a `Uint8Array` or `Array` of
bytes) or config object in the following format:

    {
        salt: // 8-byte Uint8Array or Array of bytes
        personalization: // 8-byte Uint8Array or Array of bytes
        key: // 0-32-byte Uint8Array or Array of bytes
    }

All keys in config are optional.


#### .update(data[, offset, length])

Updates the hash with data (a `Uint8Array` or `Array` of bytes).  starting at
the given `offset` (optional, defaults to 0) and consuming the given `length`
(optional, defaults to the length of `data` minus `offset`).

Returns this instance to enable method chaining.


#### .digest()

Returns a `Uint8Array` with the digest of consumed data. Further updates will
throw error. Repeat calls of `digest()` will return the same digest.


#### .hexDigest()

Like `digest()`, but returns a hex-encoded string.


#### BLAKE2s.digestLength = 32

Maximum digest length.


#### BLAKE2s.blockLength = 64

Block size of the hash function.


#### BLAKE2s.keyLength = 32

Maximum key length.

#### BLAKE2s.personalizationLength = 8

Length of personalization parameter.

#### BLAKE2s.saltLength = 8

Length of salt parameter.


Example
-------

```javascript
var h = new BLAKE2s(32);
h.update(new Uint8Array([1,2,3]));
h.hexDigest();  // returns string with hex digest
h.digest();     // returns Uint8Array

// Keyed:
var key = new Uint8Array(BLAKE2s.keyLength);
window.crypto.getRandomValues(key);
var h = new BLAKE2s(32, key);
...

// Keyed and salted:
var key = new Uint8Array(BLAKE2s.keyLength);
var salt = new Uint8Array(BLAKE2s.saltLength);
window.crypto.getRandomValues(key);
window.crypto.getRandomValues(salt);
var h = new BLAKE2s(32, { key: key, salt: salt });
...

// Personalized:
var data = new Uint8Array([1, 2, 3]);
var pers1 = new Uint8Array([1, 0, 0, 0, 0, 0, 0, 0]);
var h1 = new BLAKE2s(32, { personalization: pers1 });
h1.update(data);

var pers2 = new Uint8Array([2, 0, 0, 0, 0, 0, 0, 0]);
var h2 = new BLAKE2s(32, { personalization: pers2 });
h2.update(data);

h1.hexDigest() !== h2.hexDigest() // true

```