Password Generator: Create Cryptographically Secure Passwords Online

What Is a Cryptographically Secure Password?

A cryptographically secure password is one generated using a cryptographically secure pseudorandom number generator (CSPRNG). Standard random functions in many programming languages use deterministic algorithms seeded by a predictable value such as the current timestamp. A CSPRNG, by contrast, uses operating-system-level entropy sources — hardware events, thermal noise, interrupt timing — to produce values that are statistically indistinguishable from true randomness.

The Web Crypto API's `crypto.getRandomValues()` method is the browser-side standard for CSPRNG access. It ensures that even if an attacker knows the tool's source code, they cannot predict what password was generated for a given session. This property — called computational unpredictability — is the foundation of password security.

Password entropy is a measure of how difficult a password is to guess, expressed in bits. An 12-character password using all four character classes (uppercase, lowercase, digits, symbols — a pool of ~94 characters) has roughly 79 bits of entropy. Modern security guidelines recommend at least 72 bits; 96+ bits is ideal for high-value accounts.

How to Use This Tool

Follow these steps to generate a secure password tailored to your needs.

1. 1

   Set the password length

   Use the length slider or input to choose how many characters your password should contain. For most accounts, 16–24 characters is a good balance. For master passwords or encryption keys, consider 32+ characters.

2. 2

   Choose character sets

   Toggle uppercase letters (A–Z), lowercase letters (a–z), digits (0–9), and symbols (!@#$%^&* etc.) on or off. Including all four character classes maximizes entropy for a given length.

3. 3

   Apply optional rules

   Enable options such as 'Require at least one of each selected type' to guarantee the generated password meets common policy requirements. You can also exclude ambiguous characters like 0, O, l, and 1 for passwords that need to be read aloud.

4. 4

   Click Generate

   Press the Generate button to create a new password instantly. Each click produces a completely independent, fresh random password — there is no reuse of previous outputs.

5. 5

   Copy and store securely

   Click Copy to send the password to your clipboard. Immediately save it to a reputable password manager such as Bitwarden, 1Password, or KeePass. Never store passwords in plain-text files or email.

Common Use Cases

Strong random passwords are needed in many situations beyond just personal accounts.

• Creating unique login credentials for every website to prevent credential-stuffing attacks after data breaches.
• Generating strong master passwords for password managers and encrypted vaults.
• Producing temporary passwords for new employee accounts that must be changed on first login.
• Setting up service account passwords for databases, APIs, and server configurations.
• Creating passphrases and encryption keys for PGP, SSH, and disk encryption where complexity and uniqueness are critical.

Tips and Best Practices

A generated password is only as safe as how you handle it. Follow these best practices.

• Use a different password for every account. Reusing passwords means a single breach exposes all your accounts.
• Always store generated passwords in a dedicated password manager — never in browser autofill alone, spreadsheets, or sticky notes.
• Aim for at least 16 characters. Length contributes more to entropy than complexity alone, and longer passwords are harder to crack even if the character set is smaller.
• Enable multi-factor authentication (MFA) on all accounts in addition to using a strong password. MFA limits the damage if a password is ever compromised.
• Rotate passwords for high-value accounts periodically (every 6–12 months) and immediately after any suspected breach or when sharing access ends.

Security Considerations

All password generation in this tool happens entirely in your browser using the Web Crypto API. No passwords, settings, or preferences are transmitted to any server. You can verify this by opening the browser's developer tools and inspecting the Network tab — there are no outgoing requests during generation.

The clipboard is the main risk surface after generation. On shared or public computers, clear the clipboard immediately after pasting the password. Many password managers include clipboard auto-clear features that help with this.

Be cautious about browser extensions that have clipboard or page access; a malicious extension could read clipboard contents. Consider generating and using passwords in a private browsing window if you're on an untrusted system.

Frequently Asked Questions