Generating Strong Passwords — Best Practices for 2025

In 2024, "123456" was still one of the most commonly used passwords. Despite decades of warnings, weak passwords remain the leading cause of account compromises. This guide covers what makes a password genuinely strong and how to generate and manage them properly.

Use Intoolhub's Password Generator to create strong passwords while reading — all generation happens in your browser.

What Makes a Password Strong?

Password strength comes down to two factors: length and entropy.

Length

Every extra character multiplies the number of possibilities an attacker must search. With a 94-character printable ASCII set:

At a trillion guesses per second (faster than any real-world attack), cracking a random 16-character password would take over a trillion years.

Minimum recommendation: 16 characters for important accounts.

Character Set (Entropy)

Using only lowercase letters gives you 26 options per character. Adding uppercase, numbers, and symbols expands this:

• Lowercase only: 26 options per character
• • Uppercase: 52 options
• • Digits: 62 options
• • Symbols: 94 options

Doubling the character set has less impact than adding one more character, but both matter.

What Makes a Password Weak?

Dictionary words

Even with substitutions like p@ssw0rd, dictionary attacks test millions of common patterns. Leetspeak substitutions are well-known and don't add meaningful entropy.

Personal information

Birthdates, names, pet names, and addresses are the first things targeted in a targeted attack.

Patterns

Keyboard walks (qwerty, 123456), repeated characters (aaaaaa), and incrementing passwords (MyPassword1, MyPassword2) are trivially enumerated.

Reuse

If one service is breached and you reuse passwords, all your accounts are exposed. Have I Been Pwned lists billions of compromised credentials.

How Cryptographic Random Generation Works

The Password Generator on Intoolhub uses the browser's crypto.getRandomValues() API — the same cryptographic randomness used for TLS and key generation.

function generatePassword(
  length = 16,
  charset = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*'
) {
  const array = new Uint32Array(length)
  crypto.getRandomValues(array)
  return Array.from(array, (x) => charset[x % charset.length]).join('')
}

This is not the same as Math.random(), which is a deterministic pseudo-random function unsuitable for security purposes.

Password Managers

Generating a strong password only solves half the problem — you also need to store it safely. A password manager:

• Stores all passwords encrypted with a single master password
• Auto-fills credentials, preventing phishing (you can't fill a password on the wrong site)
• Generates unique passwords for every account
• Syncs across devices

Recommended options: Bitwarden (open source, free tier), 1Password, KeePassXC (local only).

Multi-Factor Authentication (MFA)

Even a perfect password can be stolen through phishing or a server breach. MFA adds a second requirement:

• TOTP apps (Authenticator, Aegis) — recommended
• Hardware keys (YubiKey) — strongest option
• SMS codes — better than nothing, but SIM-swap attacks are a known risk

Enable MFA on every account that supports it, especially email and financial accounts.

Quick Password Generation Guide

1. Open the Password Generator
2. Set length to 20+ characters
3. Enable uppercase, lowercase, numbers, and symbols
4. Click Generate
5. Copy the password directly into your password manager

Never type a generated password into a text document, email, or chat — go directly from generator to password manager.