Lock PDF with Password
Password-protect any PDF with AES-256 encryption online for free. Set user and owner passwords to prevent unauthorised access. No upload needed.
About Lock PDF
Protect sensitive PDFs with AES-256 encryption directly in your browser. Set a user password to control who can open the file, and a separate owner password to restrict printing, copying, and editing. The locked PDF works with all standard PDF readers including Adobe Acrobat, Preview, and browser viewers. No file ever leaves your device.
Frequently Asked Questions
What encryption level is used?
AES-256 — the strongest PDF encryption standard used by banks and governments.
Can I set different passwords for opening and editing?
Yes — set an owner password for editing permissions separately from the user password for opening.
Will the locked PDF work on all devices?
Yes — password-protected PDFs are supported by all PDF readers including Adobe Acrobat, Apple Preview, and browser viewers.
Is my PDF safe during the process?
Yes. Your file is processed locally in your browser and never uploaded to any server.