hkdfSync - crypto - Node documentation

Provides a synchronous HKDF key derivation function as defined in RFC 5869. The given ikm, salt and info are used with the digest to derive a key of keylen bytes.

The successfully generated derivedKey will be returned as an ArrayBuffer.

An error will be thrown if any of the input arguments specify invalid values or types, or if the derived key cannot be generated.

import { Buffer } from 'node:buffer';
const {
  hkdfSync,
} = await import('node:crypto');

const derivedKey = hkdfSync('sha512', 'key', 'salt', 'info', 64);
console.log(Buffer.from(derivedKey).toString('hex'));  // '24156e2...5391653'

Parameters

digest: string

The digest algorithm to use.

ikm: BinaryLike | KeyObject

The input keying material. Must be provided but can be zero-length.

salt: BinaryLike

The salt value. Must be provided but can be zero-length.

info: BinaryLike

Additional info value. Must be provided but can be zero-length, and cannot be more than 1024 bytes.

keylen: number

The length of the key to generate. Must be greater than 0. The maximum allowable value is 255 times the number of bytes produced by the selected digest function (e.g. sha512 generates 64-byte hashes, making the maximum HKDF output 16320 bytes).

Return Type

ArrayBuffer