Generate a Secure Random Password Using Web Crypto API and Javascript

crypto.js

// Check if the Crypto API is available
if (window.crypto && window.crypto.getRandomValues) {
  // Crypto API is available
} else {
  // Crypto API is not supported, provide alternative method
  console.error("Crypto API not supported in this browser.");
}

// Function to generate a secure random password
function generateRandomPassword(length, includeUppercase, includeLowercase, includeNumbers, includeSpecialChars) {
  const uppercaseChars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
  const lowercaseChars = 'abcdefghijklmnopqrstuvwxyz';
  const numberChars = '0123456789';
  const specialChars = '!@#$%^&*()-=_+[]{}|;:,.<>?/';

  let allChars = '';
  let password = '';

  if (includeUppercase) allChars += uppercaseChars;
  if (includeLowercase) allChars += lowercaseChars;
  if (includeNumbers) allChars += numberChars;
  if (includeSpecialChars) allChars += specialChars;

  const allCharsLength = allChars.length;

  for (let i = 0; i < length; i++) {
    const randomIndex = Math.floor(window.crypto.getRandomValues(new Uint32Array(1))[0] / (0xFFFFFFFF + 1) * allCharsLength);
    password += allChars.charAt(randomIndex);
  }

  return password;
}

// Define password criteria
const passwordLength = 12;
const includeUppercase = true;
const includeLowercase = true;
const includeNumbers = true;
const includeSpecialChars = true;

// Generate a random password using the defined criteria
const generatedPassword = generateRandomPassword(passwordLength, includeUppercase, includeLowercase, includeNumbers, includeSpecialChars);

// Use the generated password
console.log('Generated Password:', generatedPassword);

Read the code explanation at this Web Crypto API blog post