Jul 24, 2026 · 4 min read · Security

Generating Strong Passwords (With Honest Entropy Math)

This generator exists because Protect PDF deserves better passwords than a pet’s name and a birthday. It creates them cryptographically, on-device, and tells you honestly how strong they are - in bits of entropy.

How to use it

1. Open Password Generator (no file involved).
2. Set the length and character classes; ambiguous look-alikes (Il1O0) can be excluded.
3. Copy the password - a fresh one generates on every click.

Try it now: open the Password Generator tool - no account, no upload, free.

What happens under the hood

Randomness comes from the browser’s cryptographic RNG, with rejection sampling to eliminate the modulo bias naive generators have. The entropy readout is log₂ of the search space: every +10 bits multiplies an attacker’s work a thousandfold. 80+ bits is beyond brute force for anything you’ll protect with a PDF.

Tips for better results

• Length beats cleverness: 20 simple-charset characters outperform 10 symbol-laden ones.
• Generated passwords are never stored or transmitted - copy it into a password manager immediately.

Privacy, in one sentence

Your file is read into your browser's memory, processed there by JavaScript and WebAssembly, and handed back to you as a download - no server ever sees a byte of it. Close the tab and nothing remains.