How short can the password be?

At least 4 characters; a shorter one is asked again. A longer password is still the safer choice.

What does “block printing and copying” turn off?

Printing, editing and copying text out of the file. Access for screen readers stays on.

Can I add a new password to a PDF that already has one?

No. An encrypted PDF is refused. Remove the current password first, then protect the file again.

Tools ›

Password-protect a PDF (AES-256)

Encrypt a PDF with a password, optionally blocking printing and copying. The password never leaves your browser.

Open Password-protect PDF →Free · no sign-up · your file never leaves your browser

When you'd use it

Emailing your tax return to an accountant and sending them the password by text message.
Keeping scanned passport and ID copies on a shared family computer.
Sending a draft contract a client can read but not print or copy from.

Just say what you need

There are no menus to learn. Drop your file on pdfagents.ai and type it the way you would say it:

“protect this with a password”
“encrypt it”
“lock it and block printing”

How it works

Drop the PDF.
Type the password and choose the permissions.
Download the encrypted PDF.

There is no recovery if the password is lost.

Questions

How short can the password be?: At least 4 characters; a shorter one is asked again. A longer password is still the safer choice.
What does “block printing and copying” turn off?: Printing, editing and copying text out of the file. Access for screen readers stays on.
Can I add a new password to a PDF that already has one?: No. An encrypted PDF is refused. Remove the current password first, then protect the file again.

Guides

Password-protect a PDF with AES-256, or remove a password

Private, and it keeps going

Your document is opened and saved on your own device, never uploaded. When the result is ready, type the next request (rotate, compress, add a password) and it applies to the result.

Password-protect PDF, right now

The PDF encrypted with a password (AES-256).

Open Password-protect PDF →

Doing this often? The free Mac app runs this agent on whole folders, offline, with no page limit. See the Mac app →