Protect PDF
Runs in your browserAdd a password to a PDF in your browser. Nothing is uploaded and there is no limit. Set the password that opens the document, and choose separately whether a reader may print, copy or change it.
or drop them here, or paste
One file. It stays on your device.
Encryption happens in your browser, which matters more here than on any other tool on this site. A password sent to a server has been seen by that server. Here it is used to derive a key on your own machine and never leaves it.
Everything happens inside this page. Your file is read by JavaScript running on your own machine, and no part of it is sent anywhere.
Two passwords, two different jobs
The user password is the one that opens the document. Without it the file cannot be read at all, and the content is genuinely encrypted rather than hidden. This is real protection.
The owner password governs permissions: whether printing, copying and editing are allowed. Somebody who has the user password can open and read the file, and the permissions decide what they can do next.
If you set only a user password here, the same value is used for both. An owner password left empty makes the permission flags trivially removable, so leaving that door open while presenting the restrictions as meaningful would be dishonest.
What the permissions really do
Permissions are instructions to a reader, not a wall. A well behaved reader like Acrobat or Preview honours them, so a colleague you sent the file to will find copy disabled if you disabled it. A tool written to ignore them can ignore them.
So use permissions for what they are good at: preventing accidents and casual reuse. Do not rely on them against somebody who does not want to comply. Only the user password does that, because without it there is nothing to read.
Choosing a password
A PDF password is attacked offline. Whoever has the file can try guesses on their own hardware as fast as it allows, with no rate limit and nobody watching. That makes length the thing that matters, far more than punctuation.
Four unrelated words are stronger than a short password with symbols in it, and considerably easier to pass to a colleague over the phone. Avoid anything derived from the file name or the company, which is the first thing anyone tries.
There is no recovery
If you lose the password, the document is gone. There is no back door in this tool and no support address that can open it, because the key is derived from the password and nothing else. Write it down somewhere before you close the tab.
How to protect pdf
- 01
Add your PDF
Select or drop the file you want to lock.
- 02
Set a password
Type it, and choose what a reader is allowed to do.
- 03
Protect
Press Protect PDF and download the encrypted file.
Questions about Protect PDF
How do I password protect a PDF?
Add the file, type the password you want, choose whether printing and copying are allowed, then press Protect PDF. The encryption happens in your browser, so the password is never transmitted.
What is the difference between a user password and an owner password?
The user password is needed to open the document at all. The owner password controls what someone who has opened it may do, such as printing or copying. Setting only a user password here uses the same value for both.
Can the restrictions be bypassed?
The permission flags can, because they depend on the reader honouring them. The user password cannot: without it the content is encrypted and there is nothing to read.
What happens if I forget the password?
The document cannot be opened. There is no recovery, by us or anyone else, because the key comes from the password alone. Record it before you close the tab.