Protect PDF
Encrypt a PDF with a password using AES-256.
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Protect PDF — workspace
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How to use: Protect PDF
Choose local files or try the sample PDF. Your documents stay on your device.
Enter and confirm a password, then create an AES-256-encrypted PDF. Keep your password somewhere secure.
Create the result, check its preview, then download individual files or the ZIP archive.
What you can do
- Encrypt a PDF with a password using AES-256.
What you get
- A new PDF download; your original file remains unchanged.
What you need
- Local files
- One PDF document.
- Settings
- Enter and confirm a password, then create an AES-256-encrypted PDF. Keep your password somewhere secure.
Try an example
- Example workflow
Protect the sample with your own new password, then use Unlock PDF to test opening it.
Good to know
- Up to 50 MB per file, 100 MB per job and 200 total pages. Multi-file tools accept at most 30 files.
- Passwords must contain 12–127 UTF-8 bytes. The password is not stored or recoverable by this site.
- Keep the original document. Editing an existing digitally signed PDF can invalidate its certificate signature.
Your work stays on your device
Your files and entered values are processed in your browser and are not uploaded for processing. The website and any required processing engines still download from the site.
Questions & answers
Is Protect PDF free?
Yes. Protect PDF is free to use and does not require an account.
Are my files or entered values uploaded?
Your files and entered values are processed in your browser and are not uploaded for processing. The website and any required processing engines still download from the site.
What result can I save?
A new PDF download; your original file remains unchanged.
What should I check before using the result?
Up to 50 MB per file, 100 MB per job and 200 total pages. Multi-file tools accept at most 30 files. Passwords must contain 12–127 UTF-8 bytes. The password is not stored or recoverable by this site. Keep the original document. Editing an existing digitally signed PDF can invalidate its certificate signature.