Workspace Files stay on your device
pdf · security
Password-Protect PDF
Encrypts every page, string and stream with the PDF Standard Security Handler (RC4 128-bit, revision 3 — opens in every viewer since Acrobat 5). Nothing leaves your browser; the passwords are used only to derive the encryption keys here. This is legacy RC4 encryption, not modern AES-256; do not rely on it to protect sensitive documents.
A little guidance. A better result.
How to use Password-Protect PDF
Add legacy RC4-128 password protection to a PDF locally. Not modern AES encryption; unsuitable for sensitive-document protection.
Prepare your input
Choose a PDF and enter a password locally.
Use the workspace
Create a password-protected copy.
Check your result
Reopen the download and confirm it asks for the password.
Know the limits
This tool uses legacy RC4-128, not modern AES-256. Do not treat it as strong protection for sensitive documents.
Where does my input go?
This browser tool processes your input on your device. Optional analytics is a separate choice; it is not needed to use the tool. Keep your original until you have checked the result.
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