Frequently asked questions
Is PDFKeyFinder really free?
Yes — completely free, with no ads and no account. It runs on donations. If it helps you, you can buy me a coffee to keep the server online.
Do you upload or store my PDF?
No. Your PDF is read locally by your browser and never leaves your device. There is no file upload, so there is nothing for us to store, see, or delete.
Is it safe? Can I get a virus?
There is no file transfer to our server at all, so the usual upload risks do not apply. Everything happens inside your own browser tab.
What kinds of passwords can it recover?
Passwords that follow a guessable pattern — most commonly a name combined with a date of birth (used by many bank and government PDFs), or any structure you define with the custom pattern builder.
Which PDF encryption is supported?
RC4 40-bit and 128-bit encryption (PDF revisions 2, 3 and 4). AES-256 (revisions 5–6) is not supported.
Can it crack any password instantly?
No. If a password is long and random it cannot be guessed in a reasonable time by any tool. PDFKeyFinder works best when there is a pattern, a name, a date, or a known shape.
Is this legal?
Recovering the password to a document you own or are authorised to access is a normal, legitimate task. Using it on files you have no right to access is not allowed — see our terms.
Why is it slower on my phone?
The guessing uses your device's processor. Phones are slower than laptops, so large searches take longer. You can Stop at any time.