Protect PDF With a Password
Lock a PDF so it can only be opened with a password. The file is encrypted with AES-256 on your device, and you can also restrict printing, copying and editing.
- Files stay on your device
- No sign-up
- Free to use
How to use Protect PDF
- Drop the PDF you want to protect onto the upload area.
- Type a password and confirm it. Longer passphrases are harder to guess.
- Optionally untick printing, copying or editing to restrict what readers can do.
- Select Protect PDF and download the encrypted file. Keep the password somewhere safe.
Protect PDF features
AES-256 encryption
Uses the strongest encryption defined in the PDF standard, supported by all current PDF readers.
Password never transmitted
Encryption runs in your browser, so neither the document nor the password is sent to a server.
Permission controls
Decide whether people who open the file may print it, copy text from it or modify it.
Separate permissions password
Set a second password that is needed to change the restrictions later.
Password strength hint
A live indicator shows whether the password is weak, fair or strong.
When to use Protect PDF
- Emailing bank statements, payslips or tax documents.
- Sending a contract or proposal that only the recipient should read.
- Sharing a report that may be viewed but should not be edited or copied.
- Storing scans of identity documents in cloud storage with an extra layer of protection.
Protect PDF FAQ
What happens if I forget the password?
The file cannot be opened. AES-256 encryption has no back door and we never see your password, so it cannot be recovered. Keep an unprotected copy or store the password in a password manager.
How strong is the protection?
The encryption itself is very strong. In practice the security depends on the password: a short or common password can be guessed, while a long passphrase of several unrelated words is effectively unbreakable.
Do the print and copy restrictions really stop people?
They are honoured by mainstream PDF readers, but they are a request rather than a lock. Anyone who can open the document can view its content, so use restrictions as a deterrent and the open password as the real safeguard.
Will the protected file open in any PDF reader?
Yes, in current versions of Adobe Acrobat, Chrome, Edge, Firefox, Preview and mobile readers. Very old software released before about 2010 may not support AES-256.
Can I protect a PDF that already has a password?
Remove the existing password first with the Unlock PDF tool, then protect the unlocked copy with the new password.
Open passwords and permission passwords
PDF security has two layers. The open password (also called the user password) encrypts the document: without it, the contents are unreadable. The permissions password (owner password) controls a set of flags that tell reading software which actions to allow, such as printing or copying text.
When you set only an open password here, anyone who knows it has full control of the file. When you also restrict actions, a separate permissions password is required to lift those restrictions; if you do not supply one, a random one is generated and shown to you once so that the restrictions cannot be removed simply by re-entering the open password.
Choose a password that is long rather than complicated. Four or five unrelated words are easier to remember and far harder to crack than a short string with symbols. Share the password through a different channel from the file itself, for example by phone or message rather than in the same email.