Protect PDF
Add a password to any PDF so only people you choose can open it. The document is encrypted with AES-256 (the PDF standard's R6 algorithm) using the Web Crypto API — everything runs locally in your browser, so your file and your password never touch a server. Optionally set a separate owner password for permission-level control. Your document and password never leave your device.
Your files never leave your device. All processing happens on your device. No uploads, ever.
How to use Protect PDF
- 1
Choose a PDF
Upload the file you want to protect.
- 2
Set a password
Pick a strong password (and optionally an owner password).
- 3
Protect
AES-256 encryption runs locally, fast.
- 4
Download
Save your protected PDF and share the password securely.
Strong local encryption
Uses AES-256 R6 via the Web Crypto API — the same scheme Preview and Acrobat read. No password or file ever leaves your browser.
Two passwords, if you want
Set the open password anyone needs to read the file, and optionally a separate owner password for stronger permission control.
Private by design
With zero server round-trips, encrypting a PDF here is like doing it on your own machine.
Frequently asked questions
Is my password sent to a server?
Never. AES-256 encryption runs entirely in your browser with the Web Crypto API.
Which algorithm is used for protection?
AES-256 using the PDF 2.0 R6 standard, compatible with Preview, Acrobat and most readers.
Can I remove the password later?
Yes — use the Unlock PDF tool with the same password to remove protection.
What is an owner password?
An optional second password referenced by PDF readers to control printing and editing permissions.
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Last updated 8 August 2026