Password Protect a PDF
Put a password on a PDF before it leaves your hands.
Drop a PDF
Anyone who opens it will have to type the password you choose.
Guide: A password that every reader asks for3 min read
A password that every reader asks for
Drop the PDF, type the password and save: the copy is encrypted with AES-256, and Acrobat, the browser's viewer, Preview and the phone's files app all ask for the password before showing a single page. The original on your computer is left as it was, which is the copy to keep if you might forget the password.
Send the password by a different channel from the file — a message, a call — or the protection does nothing: whoever intercepts the email gets both.
Print, copy and edit
The three switches set the document's permissions. A reader that honours them greys out Print, refuses to select text or blocks changes. They are worth setting for a contract that should not be edited, but they are a request rather than a lock: some programs ignore them. The password to open is what actually keeps the content private.
The permissions are sealed with a second, random owner password that is never shown, so typing the open password does not also lift them. To take everything off again later, Unlock PDF only needs the password you chose.
Nothing is uploaded
A document that needs a password is by definition one that should not be handed to a stranger's server. Here the encryption runs in this tab with qpdf, an open-source PDF program, and neither the file nor the password leaves your computer. To clear the author and software names before protecting it, use Remove PDF Metadata first.
Frequently asked questions
How strong is the protection?
The document is encrypted with AES-256, the strongest method the PDF format has, and the one current versions of Acrobat use. With a good password, the content cannot be read without it. The weak point is the password itself: a short word or a date can be found by a program that tries millions of guesses, so use eight characters or more with a number or a symbol.
What do the print, copy and edit switches do?
They set permissions that PDF readers honour: a reader that respects them greys out Print or refuses to select text. They are a request, not encryption — some programs ignore them. What actually keeps the content private is the password to open, which every reader has to ask for.
What if I forget the password?
Then the protected copy cannot be opened, by you or by this site. Nothing keeps a copy of the password. Keep the original unprotected file somewhere safe, or store the password in a password manager before sending the document.
Will the person I send it to be able to open it?
Yes, in any current PDF reader — Acrobat, the browser's own viewer, Preview on a Mac, the phone's files app. They will be asked for the password. Send the password separately from the file, by a different channel, or the protection does nothing.
Is the file or the password uploaded?
No. The encryption runs in this tab with qpdf, an open-source PDF program compiled for the browser. The document and the password never leave your computer.