Secure Password Generator

How Password Security Works

Password security is fundamentally about entropy, the measure of randomness and unpredictability in a password. The more entropy a password has, the more guesses an attacker needs to crack it. Entropy is measured in bits: each additional bit doubles the number of possible combinations.

Modern password cracking uses specialised hardware, a single high-end GPU can test billions of password hashes per second. This means short or predictable passwords can be broken in seconds, regardless of how "clever" they seem. True security comes from cryptographically random generation, not human creativity.

Our generator uses the Web Crypto API (crypto.getRandomValues()), a cryptographically secure pseudorandom number generator (CSPRNG) built into every modern browser. This provides the same quality of randomness used in TLS encryption and digital signatures.

Password Entropy & Estimated Crack Times

The table below shows how entropy translates to real-world cracking resistance. Times assume an offline attack at 10 billion guesses per second, a realistic throughput for fast, unsalted hashes such as MD5 or NTLM cracked on a multi-GPU rig. This is the pessimistic case: it models an attacker who obtained a weakly-hashed password database. Slow, salted algorithms (bcrypt, scrypt, Argon2) reduce attack throughput by a factor of thousands to millions, so real-world resistance for properly protected accounts is far higher.

Understanding the Three Generation Modes

Common Password Mistakes

How the Breach Check Works

Our breach check uses the Have I Been Pwned (HIBP) Pwned Passwords API with a privacy technique called k-Anonymity. Here's how it protects your password:

1. Your password is hashed locally using SHA-1 (this never leaves your browser)
2. Only the first 5 characters of the hash are sent to the HIBP API
3. The API returns all known breached hashes starting with those 5 characters (~500 results)
4. Your browser checks whether the full hash appears in the returned list

The HIBP server never sees your full password or its complete hash. Even if the connection were intercepted, an attacker would only see a hash prefix shared by hundreds of different passwords.

Password Length Recommendations by Use Case

Why You Need a Password Manager

The average person has over 100 online accounts. Remembering a unique, strong password for each is impossible without help. A password manager solves this by storing all your credentials in an encrypted vault, protected by a single master password.

The ideal workflow: use our passphrase generator to create a strong, memorable master password (6+ words). Then use our random password generator for every individual account, storing them in your password manager. This gives you maximum security with minimum effort.

Popular password managers include Bitwarden (open source), 1Password, and KeePass (offline). All of these support auto-fill, cross-device sync, and breach monitoring. The important thing is to use one, any reputable password manager is vastly better than reusing passwords.

Beyond Passwords: Two-Factor Authentication

Even the strongest password can be compromised through phishing, keyloggers, or server breaches. Two-factor authentication (2FA) adds a second layer of verification, typically a time-based code from an authenticator app, a hardware security key, or a biometric check.

Recommended 2FA methods (strongest to weakest): hardware security keys (YubiKey, Titan), authenticator apps (Authy, Google Authenticator), push notifications, and SMS codes. Avoid SMS-based 2FA when possible, as it's vulnerable to SIM-swapping attacks.

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