Free Online PDF Encryption Tool

Protect a PDF with one opening password using AES-256 encryption. Printing, copying, editing, annotation, and form permissions remain enabled.

Drop PDF here or click to open

Supports PDF files up to 100MB

Encryption Features

One opening password
AES-256 encryption
HTTPS-protected upload
Temporary output cleanup
Re-encrypt with the old password
Permissions remain enabled

How to Use

1

Upload Your PDF

Select the PDF file to protect.

2

Set Password

Enter the one password that will be required to open the PDF.

3

Download Protected PDF

Get your encrypted document.

Frequently Asked Questions

Is PDF Encryption Tool really free?+

Yes. OnePDFs is free to use, requires no account, and does not add an extra OnePDFs branding watermark; watermark tools add only the watermark you choose.

Is my PDF file safe and private?+

The PDF and password are sent over HTTPS to our processing service. The temporary output is deleted when the response finishes; interrupted-transfer leftovers enter periodic cleanup after the one-hour retention window. A browser copy can remain in this site's IndexedDB until you clear site data or the browser evicts it.

What encryption level is used?+

The service applies AES-256 encryption with one password required to open the PDF.

Can I set a separate owner password or restrict printing and copying?+

Not currently. The service uses the same password for user and owner access and keeps printing, copying, editing, annotation, and form permissions enabled.

Ready to Get Started?

Most operations are processed locally. Your files are handled securely.