Protect PDF
Add a password to any PDF with AES-256 encryption and control printing, copying and editing. Free and private — your file and password never leave this device.
Free · No sign-upHow to protect PDF
- 1. Drop your PDF above. It is read in your browser, never uploaded.
- 2. Type a strong password twice, or press Generate for a random 16-character one (it is copied for you).
- 3. Optionally open Permissions to block printing, copying or editing, then click Protect & download.
💡 Tip: Send the password through a different channel than the file — for example email the PDF and text the password.
Frequently asked questions
Is Protect PDF free?
Yes. It is 100% free with no account, no watermark and no file limit beyond your device's memory.
How strong is the encryption?
It uses AES-256, the strongest standard PDF encryption, supported by Adobe Acrobat, Preview, Chrome, Edge and modern readers. AES-128 is available for very old readers.
Is my PDF uploaded?
No. Encryption runs in your browser with the open-source qpdf engine compiled to WebAssembly, so the file and password never reach a server.
What if I forget the password?
It cannot be recovered — that is the point of strong encryption. Keep a copy of the unprotected file or store the password in a password manager.
What do the permission settings do?
They ask PDF readers to block printing, copying or editing. Reputable apps respect them, but they are not a substitute for the open password, which actually encrypts the content.