Protect PDF with Password (AES-256)
Add a password to one or more PDFs with AES-256 encryption, and choose whether printing, copying and editing are allowed.
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Runs entirely in your browser. Your files and text are never uploaded to our server.
- Instant results
- 100% free
- No sign-up
- Private
Protect PDF encrypts your PDF so it can only be opened with a password. It uses AES-256, the strongest standard PDF encryption, or AES-128 for very old PDF readers. You can also choose whether people who open the file may print, copy text, edit, comment, fill forms or change pages.
Encryption happens in your browser and your files are never uploaded. You can protect several PDFs at once with the same password. To remove a password you know, use Unlock PDF.
More about Protect PDF with Password (AES-256)How to use, good to know & FAQ
How to use Protect PDF
- Choose one or more PDF files.
- Type a password (at least 6 characters) and repeat it.
- Optionally open “Permissions and encryption” to set what is allowed and add a separate owner password.
- Click “Protect PDF” and download the protected file (or a ZIP for several).
Good to know
- Keep your password safe. It can’t be recovered, by us or anyone else.
- Permissions such as “no printing” are respected by standard PDF apps but are not a hard barrier. The open password is what keeps the content private.
- If you leave the owner password empty, the open password is also used as the owner password.
- Digital signatures in a PDF become invalid when it is encrypted, because the file changes.
Frequently asked questions
Is AES-256 secure?
Yes. AES-256 with a strong password is the strongest encryption the PDF standard offers. Use a long password with a mix of character types.
Will the PDF open on phones and Mac?
Yes. Adobe Acrobat (X and newer), Chrome, Edge, Firefox, macOS Preview and modern phone apps all open AES-256 PDFs.
Are my files uploaded?
No. The PDF is read, encrypted and saved entirely in your browser.
What is the owner password?
A second password for changing permissions. Someone who opens the file with only the open password must follow the permissions you set.
When to use Protect PDF
Use it before emailing contracts, payslips, medical or financial documents, or anything private.