BLAKE3

BLAKE3 running in JavaScript (node.js and browsers) via native bindings, where available, or WebAssembly.

npm install blake3

Additionally, there's a flavor of the package which is identical except that it will not download native Node.js bindings and use only WebAssembly:

npm install blake3-wasm

Table of Contents

• Quickstart
• API
  • Node.js
    • hash(data: BinaryLike, options?: { length: number }): Buffer
    • keyedHash(key: BinaryLike, data: BinaryLike, options?: { length: number }): Buffer
    • deriveKey(context: BinaryLike, material: BinaryLike, options?: { length: number }): Buffer
    • Hasher
      • createHash(): Hasher
      • createKeyed(key: BinaryLike): Hasher
      • createDeriveKey(context: BinaryLike): Hasher
      • hasher.update(data: BinaryLike): this
      • hasher.digest(encoding?: string, options?: { length: number })): Buffer | string
      • hasher.reader(): HashReader
      • hasher.dispose()
    • HashReader
      • reader.position: bigint
      • reader.readInto(target: Uint8Array): number
      • reader.read(bytes: number): Buffer
      • reader.view(target: Buffer): Readonly<Uint8Array>
      • reader[Symbol.iterator]
  • Browser
    • hash(data: BinaryLike, options?: { length: number }): Hash
    • keyedHash(key: BinaryLike, data: BinaryLike, options?: { length: number }): Hash
    • deriveKey(context: BinaryLike, material: BinaryLike, options?: { length: number }): Hash
    • Hash
      • hash.equals(other: Uint8Array)
      • hash.toString(encoding: 'hex' | 'base64' | 'utf8'): string
    • Hasher
      • createHash(): Hasher
      • createKeyed(key: BinaryLike): Hasher
      • createDeriveKey(context: BinaryLike): Hasher
      • hasher.update(data: BinaryLike): this
      • hasher.digest(encoding?: 'hex' | 'base64' | 'utf8', options?: { length: number })): Hash | string
      • hasher.reader(): HashReader
      • hasher.dispose()
    • HashReader
      • reader.position: bigint
      • reader.readInto(target: Uint8Array): number
      • reader.read(bytes: number): Hash
      • reader.view(target: Buffer): Readonly<Uint8Array>
      • reader[Symbol.iterator]
• Speed
• Other (JS) Implementations
• Contributing
  • Publishing

Quickstart

If you're on Node, import the module via

const blake3 = require('blake3');

blake3.hash('foo'); // => Buffer

If you're in the browser, import blake3/browser. This includes a WebAssembly binary, so you probably want to import it asynchronously, like so:

import('blake3/browser').then((blake3) => {
  blake3.hash('foo'); // => Uint8Array
});

The API is very similar in Node.js and browsers, but Node supports and returns Buffers and a wider range of input and output encoding.

More complete example:

const { hash, createHash } = require('blake3');

hash('some string'); // => hash a string to a uint8array

// Update incrementally (Node and Browsers):
const hash = createHash();
stream.on('data', (d) => hash.update(d));
stream.on('error', (err) => {
  // hashes use unmanaged memory in WebAssembly, always free them if you don't digest()!
  hash.dispose();
  throw err;
});
stream.on('end', () => finishedHash(hash.digest()));

// Or, in Node, it's also a transform stream:
createReadStream('file.txt')
  .pipe(createHash())
  .on('data', (hash) => console.log(hash.toString('hex')));

API

Node.js

The Node API can be imported via require('blake3').

hash(data: BinaryLike, options?: { length: number }): Buffer

Returns a hash for the given data. The data can be a string, buffer, typedarray, array buffer, or array. By default, it generates the first 32 bytes of the hash for the data, but this is configurable. It returns a Buffer.

keyedHash(key: BinaryLike, data: BinaryLike, options?: { length: number }): Buffer

Returns keyed a hash for the given data. The key must be exactly 32 bytes. The data can be a string, buffer, typedarray, array buffer, or array. By default, it generates the first 32 bytes of the hash for the data, but this is configurable. It returns a Buffer.

For more information, see the blake3 docs.

deriveKey(context: BinaryLike, material: BinaryLike, options?: { length: number }): Buffer

The key derivation function. The data can be a string, buffer, typedarray, array buffer, or array. By default, it generates the first 32 bytes of the hash for the data, but this is configurable. It returns a Buffer.

For more information, see the blake3 docs.

Hasher

The hasher is a type that lets you incrementally build a hash. It's compatible with Node's crypto hash instance. For instance, it implements a transform stream, so you could do something like:

createReadStream('file.txt')
  .pipe(createHash())
  .on('data', (hash) => console.log(hash.toString('hex')));

createHash(): Hasher

Creates a new hasher instance using the standard hash function.

createKeyed(key: BinaryLike): Hasher

Creates a new hasher instance for a keyed hash. For more information, see the blake3 docs.

createDeriveKey(context: BinaryLike): Hasher

Creates a new hasher instance for the key derivation function. For more information, see the blake3 docs.

hasher.update(data: BinaryLike): this

Adds data to a hash. The data can be a string, buffer, typedarray, array buffer, or array.

hasher.digest(encoding?: string, options?: { length: number })): Buffer | string

Returns the hash of the data. If an encoding is given, a string will be returned. Otherwise, a Buffer is returned. Optionally, you can specify the requested byte length of the hash.

hasher.reader(): HashReader

Returns a HashReader for the current hash.

hasher.dispose()

This is a no-op for Node.js.

HashReader

The hash reader can be returned from hashing functions. Up to 2⁶⁴-1 bytes of data can be read from BLAKE3 hashes; this structure lets you read those. Note that, like hash, this is an object which needs to be manually disposed of.

reader.position: bigint

A property which gets or sets the position of the reader in the output stream. A RangeError is thrown if setting this to a value less than 0 or greater than 2⁶⁴-1. Note that this is a bigint, not a standard number.

reader.position += 32n; // advance the reader 32 bytes

reader.readInto(target: Uint8Array): number

Reads bytes into the target array, filling it up and advancing the reader's position. It returns the number of bytes written, which may be less then the size of the target buffer if position 2⁶⁴-1 is reached.

reader.read(bytes: number): Buffer

Reads and returns the given number of bytes from the reader, and advances the position. A RangeError is thrown if reading this data puts the reader past 2⁶⁴-1 bytes.

reader.view(target: Buffer): Readonly<Uint8Array>

Returns a view of the given number of bytes from the reader. The view can be used synchronously, but must not be reused later. This is more efficient when using the webassembly version of the module.

Fewer bytes may be returned than requested, if the number is large (>1MB).

reader[Symbol.iterator]

The reader is an Iterable of Readonly<Uint8Array>s. Like the view method, the iterated arrays will be reused internally on the next iteration, so if you need data, you should copy it out of the iterated array.

Browser

The browser API can be imported via import('blake3/browser'), which works well with Webpack.

Note that you must call the load() method before using any function in the module.

import * as blake3 from 'blake3/browser-async';

blake3.load().then(() => {
  console.log(blake3.hash('hello world'));
});

hash(data: BinaryLike, options?: { length: number }): Hash

Returns a hash for the given data. The data can be a string, typedarray, array buffer, or array. By default, it generates the first 32 bytes of the hash for the data, but this is configurable. It returns a Hash instance.

keyedHash(key: BinaryLike, data: BinaryLike, options?: { length: number }): Hash

Returns keyed a hash for the given data. The key must be exactly 32 bytes. The data can be a string, typedarray, array buffer, or array. By default, it generates the first 32 bytes of the hash for the data, but this is configurable. It returns a Hash instance.

For more information, see the blake3 docs.

deriveKey(context: BinaryLike, material: BinaryLike, options?: { length: number }): Hash

The key derivation function. The data can be a string, typedarray, array buffer, or array. By default, it generates the first 32 bytes of the hash for the data, but this is configurable. It returns a Hash instance.

For more information, see the blake3 docs.

Hash

A Hash is the type returned from hash functions and the hasher in the browser. It's a Uint8Array with a few additional helper methods.

hash.equals(other: Uint8Array)

Returns whether this hash equals the other hash, via a constant-time equality check.

hash.toString(encoding: 'hex' | 'base64' | 'utf8'): string

Hasher

The hasher is a type that lets you incrementally build a hash. For instance, you can hash a fetched page like:

const res = await fetch('https://example.com');
const body = await res.body;

const hasher = blake3.createHash();
const reader = body.getReader();

while (true) {
  const { done, value } = await reader.read();
  if (done) {
    break;
  }

  hasher.update(value);
}

console.log('Hash of', res.url, 'is', hasher.digest('hex'));

Converts the hash to a string with the given encoding.

createHash(): Hasher

Creates a new hasher instance using the standard hash function.

createKeyed(key: BinaryLike): Hasher

Creates a new hasher instance for a keyed hash. For more information, see the blake3 docs.

createDeriveKey(context: BinaryLike): Hasher

Creates a new hasher instance for the key derivation function. For more information, see the blake3 docs.

hasher.update(data: BinaryLike): this

Adds data to a hash. The data can be a string, buffer, typedarray, array buffer, or array. This will throw if called after digest() or dispose().

hasher.digest(encoding?: 'hex' | 'base64' | 'utf8', options?: { length: number })): Hash | string

Returns the hash of the data. If an encoding is given, a string will be returned. Otherwise, a Hash is returned. Optionally, you can specify the requested byte length of the hash.

hasher.reader(): HashReader

Returns a HashReader for the current hash.

hasher.dispose()

Disposes of webassembly-allocated resources. Resources are free automatically via a FinalizationRegistry for hashers, but you may call this manually if you run into resource-constraint issues.

HashReader

The hash reader can be returned from hashing functions. Up to 2⁶⁴-1 bytes of data can be read from BLAKE3 hashes; this structure lets you read those. Note that, like hash, this is an object which needs to be manually disposed of.

reader.position: bigint

A property which gets or sets the position of the reader in the output stream. A RangeError is thrown if setting this to a value less than 0 or greater than 2⁶⁴-1. Note that this is a bigint, not a standard number.

reader.position += 32n; // advance the reader 32 bytes

reader.readInto(target: Uint8Array): number

Reads bytes into the target array, filling it up and advancing the reader's position. It returns the number of bytes written, which may be less then the size of the target buffer if position 2⁶⁴-1 is reached.

reader.read(bytes: number): Hash

Reads and returns the given number of bytes from the reader, and advances the position. A RangeError is thrown if reading this data puts the reader past 2⁶⁴-1 bytes.

reader.view(target: Buffer): Readonly<Uint8Array>

Returns a view of the given number of bytes from the reader. The view can be used synchronously, but must not be reused later. This is more efficient when using the webassembly version of the module.

Fewer bytes may be returned than requested, if the number is large (>1MB).

reader[Symbol.iterator]

The reader is an Iterable of Readonly<Uint8Array>s. Like the view method, the iterated arrays will be reused internally on the next iteration, so if you need data, you should copy it out of the iterated array.

Speed

Native Node.js bindings are a work in progress.

You can run benchmarks by installing npm install -g @c4312/matcha, then running matcha benchmark.js. These are the results running on Node 12 on my MacBook. Blake3 is significantly faster than Node's built-in hashing.

    276,000 ops/sec > 64B#md5 (4,240x)
    263,000 ops/sec > 64B#sha1 (4,040x)
    271,000 ops/sec > 64B#sha256 (4,160x)
  1,040,000 ops/sec > 64B#blake3 wasm (15,900x)
    625,000 ops/sec > 64B#blake3 native (9,590x)

      9,900 ops/sec > 64KB#md5 (152x)
     13,900 ops/sec > 64KB#sha1 (214x)
      6,470 ops/sec > 64KB#sha256 (99.2x)
      6,410 ops/sec > 64KB#blake3 wasm (98.4x)
     48,900 ops/sec > 64KB#blake3 native (750x)

        106 ops/sec > 6MB#md5 (1.63x)
        150 ops/sec > 6MB#sha1 (2.3x)
       69.2 ops/sec > 6MB#sha256 (1.06x)
       65.2 ops/sec > 6MB#blake3 wasm (1x)
        502 ops/sec > 6MB#blake3 native (7.7x)

Other (JS) Implementations

• Brooooooklyn/blake-hash

Contributing

This build is a little esoteric due to the mixing of languages. We use a Makefile to coodinate things.

To get set up, you'll want to open the repository in VS Code. Make sure you have Remote Containers installed, and then accept the "Reopen in Container" prompt when opening the folder. This will get the environment set up with everything you need. Then, run make prepare to install local dependencies.

Finally, make will create a build for you; you can run make MODE=release for a production release, and certainly should if you want to benchmark it.

• Rust code is compiled from src/lib.rs to pkg/browser and pkg/node
• TypeScript code is compiled from ts/*.ts into dist

Publishing

In case I get hit by a bus or get other contributors, these are the steps for publishing:

1. Get all your code ready to go in master, pushed up to Github.
2. Run make prepare-binaries. This will update the branch generate-binary, which kicks off a build via Github actions to create .node binaries for every relevant Node.js version.
3. When the build completes, it'll generate a zip file of artifacts. Download those.
4. Back on master, run npm version <type> to update the version in git. git push --tags.
5. On Github, upload the contents of the artifacts folder to the release for the newly tagged version.
6. Run npm publish.