Protect a PDF with a password
Add strong PDF encryption locally in your browser, choose practical document permissions and download a protected copy. Your PDF and passwords stay on your device.
Protect your PDF
Up to 120 MB
No PDF selected
Owner password
A separate owner password is generated locally so the encryption keys are not based on one shared password. Keep it private if you need to manage document restrictions in a compatible PDF application.
What PDF protection does
This tool creates an encrypted copy that requires the opening password in a conforming PDF reader. It also lets you set common print, copy and modification permissions. The original PDF is left unchanged.
Why this tool uses separate user and owner passwords
PDF encryption distinguishes the password used to open the file from the owner password used by compatible readers to manage restrictions. The owner password is generated locally and is different from the opening password, which avoids the insecure practice of using one password for both roles.
Important limitation about PDF permissions
Permissions are not equivalent to an unbreakable access-control system. PDF software can choose whether to honor permission flags, and tools such as QPDF can remove PDF encryption when the user has access to the file. Use the opening password as the primary protection for confidential content; do not rely on a “no copying” permission as your only security control.
Before you protect a PDF
- Keep an accessible copy of the original document.
- Store the opening password in a password manager or another secure location.
- If compatibility with a very old PDF viewer matters, test the protected copy before distributing it.
- Remember that protecting a digitally signed PDF rewrites it and can invalidate an existing signature.
Frequently asked questions
Will my PDF be uploaded?
No. The source PDF and both passwords are kept inside your browser while the local encryption worker creates the result.
Can I recover a forgotten password?
No. FreePDF Tools does not provide password guessing or recovery. Keep your opening password somewhere secure.
What if I need to remove the password later?
Use the Unlock PDF tool with the known password to create an unencrypted copy.
Can permissions stop someone from copying a PDF?
Not reliably. Permission flags are reader-enforced restrictions, not a replacement for encryption and access control.