Protect PDF
Add a password to a PDF to restrict who can open it.
Your file stays on your device — nothing is sent to our servers.
Drop your files here
or click to browse
PDF · up to 100 MB
Upload a file to continue.
How it works
Enter a password and a new AES-encrypted copy of the PDF is produced. Anyone opening the file will be prompted for the password. Encryption happens locally in your browser.
Common use cases
- Encrypting a payslip or a tax return before storing it in a shared cloud folder.
- Password-protecting a contract before sending it by email so the recipient's inbox breach doesn't leak it.
- Adding a layer of protection to a signed document that must not be modified in transit.
Privacy
This tool runs entirely in your browser. Your PDF is never uploaded to our servers — the file stays on your device from start to finish.
FAQ
What encryption is used?
AES via the @cantoo/pdf-lib library — the modern PDF encryption standard, respected by every PDF viewer including Adobe Reader, Preview, and browsers.
What happens if I lose the password?
The file cannot be recovered. There is no backdoor, no reset, no support ticket. Store the password somewhere safe (a password manager) before you close the tab.