Protect PDF - Frequently Asked Questions

The Protect PDF tool adds a password and permission restrictions to a PDF. You can:

• Require a password to open the PDF.
• Restrict printing, changing the document, copying text and images, or adding comments and filling in forms.
• Apply restrictions without an opening password.

Protected PDFs use 256-bit AES encryption, the strongest encryption in the PDF standard. The real protection comes from your password, so use 12 or more characters mixing letters, numbers and symbols. A strength meter shows how strong your password is as you type; the check runs in your browser.

• Printing: stops the PDF from being printed.
• Modification: stops changes such as editing, inserting or deleting pages.
• Copy/Extract: stops text and images from being copied.
• Annotations & Forms: stops comments, highlights and form filling.

Ticked items are blocked in the protected PDF. Reputable PDF readers follow these restrictions, but they are not as strong as an opening password: some software ignores them. For truly confidential files, set an opening password.

No. Leave the password empty to apply only the permission restrictions. Anyone can then open the PDF, but the restricted actions are blocked in PDF readers that respect them.

We cannot recover it, because we never store passwords. Keep your password somewhere safe. If you lose it, protect your original unprotected file again with a new password.

Yes, in current software: Adobe Acrobat and Acrobat Reader (version 9 or later), the PDF viewers in Chrome, Edge, Firefox and Safari, and most modern PDF apps on Android and iPhone. Very old PDF readers that do not support AES-256 cannot open it.

Send the password separately from the file, for example by phone or in a different app. Anyone who gets both the file and the password can open it.

Yes. If you know the password, Unlock PDF removes the password and restrictions. To protect many files with the same password, use Batch Protect PDF.

Yes. It works in modern browsers on Android phones, iPhones and tablets, and protected PDFs open in the PDF apps on those devices when the password is entered.

Your PDF is uploaded over an encrypted connection and protected on our own server. The server copy is deleted as soon as the protected file has been sent back to your browser. Your password is used only to encrypt the file and is never stored. Nothing is sent to a third party.