`crypto.scrypt()`

Derives a key from a password using the memory-hard scrypt algorithm.

Since Node 10.5 Spec ↗

Syntax

crypto.scrypt(password, salt, keylen[, options], callback)

Parameters

Name	Type	Required	Description
`password`	`string \| Buffer`	Yes	The password to derive a key from.
`salt`	`string \| Buffer`	Yes	A unique random salt per password.
`keylen`	`number`	Yes	The desired derived key length in bytes.
`callback`	`function`	Yes	`(err, derivedKey)` callback (use scryptSync for sync).

Returns

void — Delivers the key via callback; scryptSync returns a Buffer.

Examples

import { scrypt, randomBytes } from 'node:crypto';
import { promisify } from 'node:util';

const scryptAsync = promisify(scrypt);
const salt = randomBytes(16);
const hash = await scryptAsync('hunter2', salt, 64);
console.log(hash.toString('hex').slice(0, 16));

Output

a3f1c8e2b7d49a6e

import { scryptSync, timingSafeEqual } from 'node:crypto';

function check(password, salt, stored) {
  const h = scryptSync(password, salt, 64);
  return timingSafeEqual(h, stored);
}

Notes

Designed for password hashing: store the salt alongside the hash and use a fresh random salt per user. Verify with `timingSafeEqual`. The async form avoids blocking the event loop under this CPU-heavy work.