function

crypto.hkdfSync

digest: string,

keylen: number

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'

@param digest

The digest algorithm to use.

@param ikm

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

@param salt

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

@param info

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

@param keylen

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).

Referenced types

class ArrayBuffer

Represents a raw buffer of binary data, which is used to store data for the different typed arrays. ArrayBuffers cannot be read from or written to directly, but can be passed to a typed array or DataView Object to interpret the raw buffer as needed.

readonly [Symbol.toStringTag]: string
readonly byteLength: number
Read-only. The length of the ArrayBuffer (in bytes).
resize(
newByteLength?: number
): void;
Resizes the ArrayBuffer to the specified size (in bytes).
MDN
resize(
byteLength: number
): ArrayBuffer;
Resize an ArrayBuffer in-place.
slice(
begin: number,
end?: number
): ArrayBuffer;
Returns a section of an ArrayBuffer.
transfer(
newByteLength?: number
): ArrayBuffer;
Creates a new ArrayBuffer with the same byte content as this buffer, then detaches this buffer.
MDN
transferToFixedLength(
newByteLength?: number
): ArrayBuffer;
Creates a new non-resizable ArrayBuffer with the same byte content as this buffer, then detaches this buffer.
MDN