xcraft-core-utils/lib/crypto.js

Xcraft utils

'use strict';

var crypto = require('crypto');
const {v4: uuidV4} = require('uuid');

exports.md5 = function (data) {
  var md5 = crypto.createHash('md5');
  md5.update(data);
  return md5.digest('hex');
};

exports.sha256 = function (data) {
  var sha = crypto.createHash('sha256');
  sha.update(data);
  return sha.digest('hex');
};

exports.genToken = function () {
  return uuidV4().replace(/-/g, '');
};

// Get the number of random bytes needed and the mask
// used to generate an integer in the specified range
function getBytesSizeAndMask(range) {
  let mask = 0;
  let bitsCount = 0;
  while (range > 0) {
    mask = (mask << 1) | 1; // 0x00000011 -> 0x00000111
    range = range >>> 1; // 0x00111100 -> 0x00011110
    bitsCount++;
  }
  const bytesSize = (bitsCount + 7) >> 3; // ceil(bitsCount / 8)
  return {bytesSize, mask};
}

/**
 * Generate a random integer between min and max.
 *
 * @param {number} min - Min value.
 * @param {number} max - Max value.
 * @returns {number} A random integer between min and max
 */
function randomInt(min, max) {
  const range = max - min;
  if (range > 2147483647 || range < 0) {
    // max safe integer for bitwise operations (2147483647 = 2^31 - 1)
    throw new Error('Range must be between 0 and 2147483647');
  }

  const {bytesSize, mask} = getBytesSizeAndMask(range);
  let randomInt;
  do {
    const randomBytes = crypto.randomBytes(bytesSize);

    // Convert random bytes to an integer
    randomInt = 0;
    for (let i = 0; i < bytesSize; i++) {
      randomInt = (randomInt << 8) | randomBytes[i];
    }

    // Apply mask to reduce the number of discarded numbers
    randomInt = randomInt & mask;
  } while (randomInt > range); // Discard random numbers outside the range

  return min + randomInt;
}
exports.randomInt = randomInt;

const defaultChars =
  'abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ@+-=*&%?!_23456789';

function randomChar(chars = defaultChars) {
  const charId = randomInt(0, chars.length - 1);
  return chars[charId];
}
exports.randomChar = randomChar;

/**
 * Generate a random password.
 * @param {number} [length] - The password length.
 * @param {string} [chars] - A string with the chars to use for password generation.
 * @returns {string} A random string
 */
exports.randomPassword = function (length = 12, chars) {
  let password = '';
  for (let i = 0; i < length; i++) {
    const char = randomChar(chars);
    password += char;
  }
  return password;
};