Check a PDF password's strength
Before protecting a PDF (or to evaluate a password already in use), analyze its strength and, if you like, verify that it actually opens a given encrypted PDF file. 100% local processing in your browser — nothing is sent to a server.
Optional check: upload the protected PDF to confirm that this password actually opens it.
How it works
The strength analysis looks at the password's length and the character categories it uses (lowercase, uppercase, digits, symbols) to derive an entropy estimate in bits and a qualitative score. The open check, on the other hand, actually tries to decrypt the supplied PDF with this password: it's the only reliable way to know whether a password is the right one, since the strength analysis alone can't tell you.
Why isn't the strength score enough to tell whether the password is correct?
The strength score only measures how hard the password is to guess by brute force, independently of any PDF file. A password can be extremely strong and still simply be the wrong password for a given PDF: only an actual decryption attempt (the open check) can confirm it.
Can this tool recover a forgotten password?
No, it performs neither brute force nor dictionary attacks: it analyzes a password that you type yourself and, at best, checks whether it matches the supplied PDF. If you've completely forgotten your password, this tool can't help you recover it.
100% local processing: the analysis and verification run entirely in your browser via WebAssembly, with no network request — your password is never sent anywhere.