Add Password to PDF
Protect a PDF with a password so it can't be opened without it.
This Add Password to PDF tool encrypts a PDF with RC4 128-bit encryption so it can't be opened without the password you set — enough to require a password in any standard reader, though not the strongest encryption available. Upload a PDF, set a password, and download the protected file; nothing is uploaded to a server.
How to use
- 1Upload a PDF.
- 2Enter the password required to open it (and, optionally, a separate owner password for permissions).
- 3Click Add Password and download the protected file.
Frequently asked questions
Why would I password-protect a PDF?
Sending a sensitive document — a contract, financial statement, or ID scan — over email or a shared link, where you want basic access control beyond just the link being obscure.
What's the difference between the user and owner password?
The user password is required to open the file at all; the optional owner password separately controls permissions like printing or editing, without affecting whether the file can be opened.
How strong is the encryption?
RC4 128-bit — enough to require a password in any standard PDF reader, but not the strongest encryption available. Treat it as basic access control, not vault-grade security.
Is my PDF uploaded to a server?
No. Encryption happens entirely in your browser — your file and password never leave your device.