Protect PDF
Add a password to a PDF with AES-256 encryption
- Files never leave your device
- Runs in your browser
- Free, no sign-up, no watermark
Drop a PDF to protect with a password, or click to choose
Accepts PDF · You can also paste with Ctrl+V / ⌘V
How to use Protect PDF
Add an open password to a PDF with AES-256 encryption, right in your browser. You can also restrict printing, copying, editing, and comments. Each encrypted file is checked to open only with your password before it is offered for download.
- 1
Drop the PDF you want to protect.
- 2
Type a password under Set a password, then type it again in Confirm password.
- 3
Optional: open Advanced to limit printing, copying, editing, or comments, set a separate owner password, or switch to AES-128.
- 4
Click Protect PDF, then Download the protected file.
Frequently asked questions
Is my password sent anywhere?
No. It is used only in this tab to encrypt the file and is never stored or sent. Nobody can recover it for you, so keep it somewhere safe.
Which encryption is used?
AES-256 by default, which opens in every current PDF reader and Acrobat 9 or later. AES-128 is only for very old readers, and its passwords are limited to Latin letters, digits, and common symbols.
Do the printing and copying restrictions really stop people?
PDF readers enforce them, so they deter casual misuse, but they are not a hard barrier. The open password is the real protection.
What is the owner password for?
It lifts the restrictions. By default a random one is generated and discarded, so the open password can never lift them. Keep your original file if you may need changes later.
The PDF already has a password. Can I change it?
Yes. Enter the current password when you open the file; the new file opens only with the password you set here.