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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).

Build Status

This implementation is maintained, but will not receive new features. If you're looking for a full implementation of BLAKE2s, BLAKE2Xs and BLAKE2b, see my packages from StableLib: @stablelib/blake2s, @stablelib/blake2xs, and @stablelib/blake2b.


Via NPM:

$ npm install blake2s-js

or just download blake2s.min.js.


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.


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


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.


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);
var h = new BLAKE2s(32, key);

// Keyed and salted:
var key = new Uint8Array(BLAKE2s.keyLength);
var salt = new Uint8Array(BLAKE2s.saltLength);
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 });

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

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