Security & Privacy
How to Password Protect a PDF
Add a password to a PDF so only the people you choose can open it — including how to pick a password and how to get it to the recipient safely.
Password protection encrypts the contents of a PDF. Without the password the file is unreadable — not hidden, not restricted, genuinely encrypted. It is the right control for a payslip, a contract or a medical record sent by email.
Protect a PDF
- 1Open the Protect PDF tool and add your file.
- 2Set a password. Make it a real one, not "1234".
- 3Download the protected file.
- 4Test it by opening the download — you should be asked for the password.
Two kinds of password
| Type | What it does | How strong |
|---|---|---|
| User password (open password) | Required to open the document at all | Real encryption — the content is unreadable without it |
| Owner password (permissions) | Restricts printing, copying or editing | Advisory — readers choose to honour it |
The distinction matters enormously. An open password means the bytes are encrypted. A permissions password means the file is readable and merely asks software to behave; anything that ignores the request has full access. If the content is genuinely confidential, use an open password.
Choosing a password
- Long beats complicated. Four unrelated words are stronger and easier to relay than "P@ssw0rd!".
- Do not reuse a password you use anywhere else — this one gets shared.
- Avoid anything the recipient could guess from the document: a surname, an invoice number, a date of birth.
- Write it down somewhere you will find it. A protected PDF whose password is lost is gone.
What encryption does not do
It protects the file in transit and at rest. It does not stop the recipient forwarding it, printing it, screenshotting it or removing the password once they have opened it. Encryption controls who can open the document, not what an authorised reader does next.
If you lose the password
There is no recovery. Strong encryption without the key is exactly as intended: unreadable. Keep an unprotected original somewhere secure, or record the password properly.
Do it now
Protect PDF
Add password protection to PDF. It runs in this browser tab — your file is not uploaded anywhere.
Open Protect PDFFrequently asked questions
Can a password-protected PDF be cracked?+
A short or common password can be guessed by brute force. A long passphrase with modern encryption is not realistically breakable.
What is the difference between the two password types?+
The open password encrypts the file. The permissions password only asks readers to restrict actions, and can be ignored.
Can I remove the password later?+
Yes, if you know it. Unlock the file and save an unprotected copy.
Does protection stop someone forwarding the file?+
No. Anyone with the password can open, forward and share it.
Will the recipient need special software?+
No. Every mainstream PDF reader prompts for the password.