Web Crypto API - subtle.deriveKey doesn't return promise with ArrayBuffer + doc example bug

[JoakimCh]

The documentation says that it should, but instead it returns a promise with Buffer.

Also the example in the documentation called "Deriving bits and keys" has a bug. In subtle.importKey it is missing 'deriveKey' causing subtle.deriveKey to fail.

Buggy version:

async function pbkdf2Key(pass, salt, iterations = 1000, length = 256) {
  const ec = new TextEncoder();
  const keyMaterial = await subtle.importKey(
    'raw',
    ec.encode(pass),
    'PBKDF2',
    false,
    ['deriveBits']);
  const key = await subtle.deriveKey({
    name: 'PBKDF2',
    hash: 'SHA-512',
    salt: ec.encode(salt),
    iterations
  }, keyMaterial, {
    name: 'AES-GCM',
    length: 256
  }, true, ['encrypt', 'decrypt']);
  return key;
}

Fixed version (updated based on feedback from jasnell):

async function pbkdf2Key(pass, salt, iterations = 1000, length = 256) {
  const ec = new TextEncoder();
  const keyMaterial = await subtle.importKey(
    'raw',
    ec.encode(pass),
    'PBKDF2',
    false,
    ['deriveKey']);
  const key = await subtle.deriveKey({
    name: 'PBKDF2',
    hash: 'SHA-512',
    salt: ec.encode(salt),
    iterations
  }, keyMaterial, {
    name: 'AES-GCM',
    length: 256
  }, true, ['encrypt', 'decrypt']);
  return key;
}

[aduh95]

Would you be interested in sending a PR?

[jasnell]

The deriveBits in the example can be replaced with deriveKey :-)

[JoakimCh]

@aduh95 Would you be interested in sending a PR?

Sadly I'm not very good with Git yet, hence I would prefer that someone else does that.

[panva]

Resolved by 896dc39