Unlock PDF
Remove the password from a PDF you can open. Drop as many PDFs as you like.
Unlock PDF hands your file and password to qpdf with --decrypt, writing out a copy with the encryption removed and an -unlocked suffix. Leave the password blank for a document that only carries permission restrictions; those are lifted in the same pass. The copy is not encrypted at all, so anyone holding it can open it.
Questions
Does this crack or guess passwords?
No. It removes a password you already know, and says so when you get it wrong: "this tool removes a password you know, it does not guess one". There is no brute-force mode.
My PDF opens fine but will not let me print or copy, does this help?
Yes, and you can leave the password field blank. Plenty of PDFs carry no open password at all, only permission restrictions; qpdf's decrypt lifts those in the same pass.
What if the file was not encrypted at all?
It comes back rather than being refused, with the same content but a rewritten structure: qpdf reads and writes every file it is given, so the bytes differ and the size shifts a little. One less thing to check before you drop a batch in.
Is it legal to remove the password?
That depends on the document and where you are, and it is your call to make, the tool has no view on it. Practically, it can only ever open a file you can already open.
Can I unlock several at once?
Yes, if they share a password. Each file is decrypted separately and returned with an -unlocked suffix; one wrong password fails only its own file.
Compare
| Tool | Runs on the CLI | Live as you type |
|---|---|---|
| Unlock PDF | Yes | No |
| Password protect PDF | Yes | No |
| Flatten PDF form | Yes | No |