Guide
How to lock or unlock a PDF
Locking writes a real password into a PDF, using the same AES-256 encryption every current reader already supports. Unlocking runs the same thing backwards: given the password a file already has, it writes out the same document without it. Both happen in your browser tab — the file is never sent anywhere.
Steps
Open the tool and choose Lock or Unlock
Go to Lock/Unlock PDF. The two are one page with a switch at the top, not separate tools, because they are the same operation looked at from either end. Lock expects a file that is not protected yet; Unlock expects one that already is.
To lock a PDF, set a password to open it
Type it once, then again to confirm — a typo here means a file even you cannot open again, which is exactly what the confirm field exists to catch. A strength meter appears once you start typing; it is a suggestion, not a gate, so a short PIN is still allowed if that is genuinely all the file needs.
Add a separate permissions password, if you need one
This is optional, and it answers a different question. The password above controls whether the file opens at all; a permissions password restricts printing, copying or editing even for a reader who is never asked for a password at all — useful when a document should be readable by anyone but not passed around freely. Whoever knows the permissions password gets full access, restrictions lifted.
Lock and download
The file comes back exactly as it was, with a real password now standing between it and anyone who opens it.
To unlock a PDF, switch tabs and enter its password
This only ever works with the password the file was actually protected with. If a field lets you submit a blank password, that is because the file itself allows opening it without one — some files only restrict what you can do once inside, not whether you can look.
Unlock and download
A wrong password says so plainly rather than failing silently. Once accepted, the download is the same document with no protection at all — printing, copying and editing all work again.
A password only protects a file from someone who does not have it. If you send the password over the same channel as the file — the same email, the same message — you have not really restricted anyone. Send it a different way, and treat the permissions password the same as the password to open it: knowing either one gets past the other.
Common questions
Can this tool remove a password I do not know?
No, and it is not trying to. Unlocking here only ever works with the correct password — it does not guess, recover or attempt to bypass protection on a file that is not yours to open. If you have genuinely lost a password, this is not the tool for that, and no tool that runs in a browser tab honestly is.
Is AES-256 actually strong?
Yes — it is the encryption ISO 32000-2 (the current PDF standard) recommends, and the only cipher this tool ever writes. Older PDF tools default to 40-bit or RC4 encryption from the 1990s, which modern software can break quickly and some viewers now flag outright; this tool never produces that.
What's the difference between the two passwords?
The first controls whether the file opens at all. The second, optional one controls what a reader can do once it is open — print it, copy from it, edit it — and matters even if the first password is never set, or is known to everyone. Knowing the second password grants full access regardless of the restrictions it defines.
What happens if I forget the password I just set?
The file is genuinely locked — that is what a real password means. Nothing on this site can recover it, because nothing on this site ever saw it; it existed in your browser tab for as long as it took to encrypt the file, and nowhere else. Keep an unlocked copy somewhere if that matters to you.
Does locking change the document itself?
No. Every page, its text and images, are carried across untouched — only an access-control layer is added around them. Unlocking removes that layer the same way, by copying every page into a fresh, unencrypted document.
Is my file uploaded?
No. Both directions run in your browser tab, and the file never leaves your device.