Why is this the one tool that needs a server?

Encryption is genuinely impossible in a browser — there is no JavaScript implementation of PDF encryption that a reader will accept. The file goes to the document service, is encrypted with qpdf, and comes straight back.

Is my password stored?

No. It is passed to the converter to do the work and is never written to disk or logged.

Nobody can recover it. That is the point of encryption — keep the password somewhere safe before you send the file on.

Protect PDF

Lock a document with a password so it cannot be opened without one.

Processed on our server, then deletednew

Browsers cannot write encrypted PDFs, so this runs on our server. The file and password are deleted as soon as the protected copy comes back.

Report a problem

How to use Protect PDF

Choose the PDF you want locked.
Set the password that will be needed to open it.
Press Protect, then download the encrypted copy from the result below.

Questions

Why is this the one tool that needs a server?: Encryption is genuinely impossible in a browser — there is no JavaScript implementation of PDF encryption that a reader will accept. The file goes to the document service, is encrypted with qpdf, and comes straight back.
Is my password stored?: No. It is passed to the converter to do the work and is never written to disk or logged.
What if I forget it?: Nobody can recover it. That is the point of encryption — keep the password somewhere safe before you send the file on.

Auf Deutsch: PDF mit Passwort schützen · En français : Protéger un PDF par mot de passe