What this tool does
Upload a PDF (up to 24 MB), enter an open password twice, and decide what viewers are allowed to do: print, copy text, annotate or change the document. The file is encrypted with AES-256. The result is a PDF that asks for the password to open.
Passwords and permissions
- The open password is required to read the file. Without it, the content can’t be viewed.
- The owner password controls permissions. This page doesn’t ask for one: the tool generates a random owner password, so that the permission settings are actually enforced by viewers. You won’t know that generated password, and that is fine unless you later need to change permissions on this exact file.
- Permissions are advisory. Viewers are supposed to honour them, but some tools ignore them, and a person who can open the file can often get around “no copy” or “no print”. Only the open password gives real protection.
After encrypting, the tool checks that the file is locked, that a wrong password is refused, and that the right one works.
Choosing a password
Use a long passphrase. AES-256 is strong, but a short or common password can be guessed, which is how most protected files are broken. Share the password through a different channel than the file.
Privacy and honesty
The file and password are sent to the server, so the conversion is not end-to-end private. The password is passed to a Python script in a temporary configuration file, which is removed afterwards. The output is held temporarily with a download link that expires after 15 minutes. For very sensitive documents, consider encrypting with software on your own computer. Up to 10 requests a minute are allowed.
To reverse it, use Unlock PDF.
How to use it
- Choose the PDF (up to 24 MB).
- Enter the Open Password twice.
- Tick the actions viewers may take: print, copy, annotate or change the document.
- Press Protect PDF, then Download Protected PDF. Test that the password works.
Which encryption does it use?
AES-256. This page doesn’t offer another level.
Do permission restrictions really stop copying?
Only for well-behaved viewers. Treat them as a request, not security.
Can I recover the file if I forget the password?
No. Keep the password safe, because there is no recovery.
Is my document private on the server?
It is uploaded for processing and stored temporarily. If that’s not acceptable, encrypt locally instead.
What can I restrict?
Printing, copying text and images, annotating, and changing the document. Tick the actions you want to allow. These permissions are advisory, so only the open password gives real protection.