How to password-protect a PDF, and which encryption to choose
A password on a PDF stops anyone without it from opening the file. How strong that protection is depends on the encryption and on the password you choose.
Protect the file
- Open Protect PDF and add your PDF.
- Type a password twice.
- Keep AES-256 selected. It opens in every current PDF reader: Adobe Reader 9 and later, Chrome, Edge, and phone apps. Choose AES-128 only for very old software.
- Choose whether people may print, copy text or edit, then click Protect PDF.
Choose a good password
- Use at least 12 characters. A short phrase of unrelated words works well.
- Do not reuse your email or bank password.
- Send the password by a different route than the file, for example by phone or text message.
Need one? Password generator makes strong passwords in your browser.
Forgot the password?
It cannot be recovered: that is the point of encryption. If you know the password and want to remove it, use Unlock PDF.
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