amazon-cognito-identity-js/lib/utils/cryptoSecureRandomInt.js

Amazon Cognito Identity Provider JavaScript SDK

"use strict";

exports.__esModule = true;
exports["default"] = cryptoSecureRandomInt;
var crypto;

// Native crypto from window (Browser)
if (typeof window !== 'undefined' && window.crypto) {
  crypto = window.crypto;
}

// Native (experimental IE 11) crypto from window (Browser)
if (!crypto && typeof window !== 'undefined' && window.msCrypto) {
  crypto = window.msCrypto;
}

// Native crypto from global (NodeJS)
if (!crypto && typeof global !== 'undefined' && global.crypto) {
  crypto = global.crypto;
}

// Native crypto import via require (NodeJS)
if (!crypto && typeof require === 'function') {
  try {
    crypto = require('crypto');
  } catch (err) {}
}

/*
 * Cryptographically secure pseudorandom number generator
 * As Math.random() is cryptographically not safe to use
 */
function cryptoSecureRandomInt() {
  if (crypto) {
    // Use getRandomValues method (Browser)
    if (typeof crypto.getRandomValues === 'function') {
      try {
        return crypto.getRandomValues(new Uint32Array(1))[0];
      } catch (err) {}
    }

    // Use randomBytes method (NodeJS)
    if (typeof crypto.randomBytes === 'function') {
      try {
        return crypto.randomBytes(4).readInt32LE();
      } catch (err) {}
    }
  }
  throw new Error('Native crypto module could not be used to get secure random number.');
}