fritzbox-api/src/hashUtil.mjs

Straightforward, lightweight and extendable Node.js library to communicate with FRITZ!Box devices

// Copyright (c) 2026, Thorsten A. Weintz. All rights reserved.
// Licensed under the MIT license. See LICENSE in the project root for license information.

import { createHash, pbkdf2Sync, randomBytes } from 'crypto';

/**
 * Utility class providing hashing and key derivation functions.
 * Contains only static methods and is not intended to be instantiated.
 */
class HashUtil {

    /**
     * Creates an MD5 hash from the given input.
     *
     * @param {string|Buffer} data Input data to hash.
     * @returns {string} Hash value as a hexadecimal string.
     */
    static md5 = (data) =>
        createHash('md5').update(data).digest('hex');

    /**
     * Derives a key using the PBKDF2 (Password-Based Key Derivation Function 2) algorithm.
     *
     * @param {string|Buffer} value Input value (e.g., password or intermediate hash).
     * @param {string} saltHex Salt as a hexadecimal string.
     * @param {number|string} iterations Number of iterations (work factor).
     * @param {number} [keyLength=32] Length of the derived key in bytes.
     * @param {string} [digest='sha256'] Hash algorithm to use (e.g., 'sha256', 'sha512').
     * @returns {Buffer} Derived key as a Buffer.
     */
    static pbkdf2 = (value, saltHex, iterations, keyLength = 32, digest = 'sha256') =>
        pbkdf2Sync(
            value,
            Buffer.from(saltHex, 'hex'),
            Number(iterations),
            keyLength,
            digest
        );

    /**
     * Generates a cryptographically secure random hex string.
     *
     * @param {number} size Number of random bytes.
     * @returns {string} Random value as hex string.
     */
    static randomHex = (size = 8) =>
        randomBytes(size).toString('hex');
}

/**
 * Exports @see HashUtil as default class.
 */
export default HashUtil;