PDF Protect Tool Online

How to Password Protect a PDF

1. Drop your PDF onto the tool, or click Choose PDF File. It needs to be a .pdf without an existing password.
2. Type an Open Password in the Password tab. This is the password people must enter to view the file. The dice button generates a random 16-character one, so copy it before you leave the page.
3. Check the Permissions tab. Print, Copy text, Edit content, Annotations and Fill forms can each be switched on or off. Copy text and Edit content start switched off. If you only want a password, switch every permission on. If you want the restrictions to hold, add an Owner Password too.
4. Add a text watermark in the Watermark tab if you want one, such as CONFIDENTIAL. It is optional.
5. Click Protect PDF. The encryption runs in your browser tab.
6. Download Protected PDF. The copy is saved with _protected added to the file name.

Why Use This PDF Protection Tool

• Your file stays on your device. The PDF and both passwords are handled by code running in your browser. Nothing is sent to a server.
• 256-bit AES encryption. The same encryption level modern PDF readers use for password-protected files.
• Two passwords, two jobs. The open password controls who can view the file. The owner password controls who can change the permissions.
• Permissions you pick one by one. Printing, copying text, editing, annotations and form filling can each be allowed or blocked.
• Optional text watermark. Choose size, rotation, color, opacity, and whether it sits in the center, repeats across the page, or goes in a corner.
• Pages are not flattened. The tool encrypts your original PDF instead of converting pages to images, so text stays text and quality is not reduced.
• Password strength check. A meter rates what you type, from Weak to Very Strong.

Good to know: permission switches are instructions that PDF readers follow, and some software ignores them. Only the open password actually keeps people out of the file. The tool cannot protect a PDF that already has a password, so run it through Unlock PDF first. The watermark is text only and is set in Helvetica Bold.

FAQ

How do I password protect a PDF?

Drop your PDF onto the tool, type an open password, click Protect PDF and download the result. Copy text and Edit content start switched off, so either turn them on in the Permissions tab or add an owner password, otherwise the tool stops and asks for one. Your original file is not changed.

Is my PDF uploaded anywhere?

No. The encryption runs in your browser using an engine hosted on pdffans.com, so the PDF and your passwords never leave your device.

How strong is the encryption?

The tool applies 256-bit AES, the highest level the PDF format supports. In practice the password is the weak point, so use the dice button to generate a long random one.

What is the difference between the open password and the owner password?

The open password is needed to view the file at all. The owner password is needed to change the permissions, and it is what makes the print, copy and edit restrictions apply. If you set only an open password with every permission on, the same password is used for both.

Can I recover a forgotten password?

No. The password exists only on your device and inside the encrypted file, and we never see it, so there is nothing we could reset. Keep an unprotected copy of the original somewhere safe.

Is there a file size limit?

Each PDF can be as large as your plan allows; the limit is shown on this page. Very large files take longer because the work happens on your own device.