Protect PDF
Add password protection to PDF files free. AES-256 encryption, permission controls, no upload. Protect your documents in the browser.
How to Use Protect PDF
- Upload the PDF you want to protect by dragging it into the drop zone.
- Enter a strong password in the password field.
- Choose permissions — whether to allow printing, copying, and editing.
- Click Protect PDF and download your encrypted document.
Why Choose Krynn Tools for Protect PDF?
- AES-256 Encryption: Your PDF is protected with military-grade encryption that prevents unauthorized access.
- Permission Controls: Restrict printing, copying, and editing while allowing viewing with a password.
- No Server Storage: Encryption happens entirely in your browser. Your PDF and password are never transmitted anywhere.
- Instant Protection: Protect any PDF in seconds — no software installation or account creation required.
Frequently Asked Questions
How strong is the password protection?
Krynn Tools uses AES-256 encryption, which is the same standard used by banks and government agencies. Your protected PDF is virtually unbreakable without the password.
Can I remove the password later?
Yes. Use our Unlock PDF tool to remove the password protection. You'll need to enter the password to decrypt the file.
Will the protected PDF work in all PDF readers?
Yes. The encryption follows the standard PDF specification, so Adobe Acrobat, Preview, Chrome, and all major PDF readers will prompt for the password correctly.
Does protecting a PDF change its file size?
Very slightly — adding encryption metadata adds a few kilobytes. The actual content remains unchanged.