How to Password-Protect a PDF

Two passwords, two jobs

• Password to open: nobody can read the document without it. This is the one that keeps it private.
• Password to change permissions: the document opens for anyone, but this password is needed to change what readers may do, such as print or copy text.

You can set either or both. You need at least one.

How to password-protect a PDF in Monstera

1. Open the PDF

   Install Monstera free from the Microsoft Store and open the document.

2. Open Permissions

   In the rail, choose Protect, then Permissions in the Encryption group. Its full name is Password and permissions.

3. Choose the encryption

   In Encryption, choose AES-256 (recommended). The older choices are there only for very old readers.

4. Set the passwords

   Type a Password to open, a Password to change permissions, or both.

5. Choose the permissions

   Under Allow without the permissions password, untick anything readers should not do, such as Print or Copy text and images.

6. Protect and save

   Choose Protect document, then save. The protection is applied when you save.

Remove a password

Open the document with its password, open Permissions again, choose None — remove the password in Encryption, choose Remove protection and save.

Good to know

• Keep your password safe. Monstera cannot recover a lost password. It holds the password only while the document is open, so your changes are saved still protected, and forgets it when you close the file.
• Permissions depend on the reader. Print and copy limits are honoured by PDF readers that choose to honour them; the file itself cannot force them. For real privacy, use a password to open.
• No readable copies left behind. When you protect a document, Monstera also encrypts the older copies it keeps beside it, such as backups and undo copies.
• Protected documents can still be signed, and they keep their password and permissions. See how to sign a PDF with a certificate.

Questions

What encryption does Monstera use?

AES-256, which is the recommended choice in the Password and permissions window. Older choices are offered only for very old readers.

Can Monstera recover a forgotten PDF password?

No. Monstera cannot recover a password, so keep it somewhere safe.

Can I stop people printing or copying my PDF?

You can untick Print and Copy text and images. These limits are honoured by PDF readers that choose to honour them, so for real privacy set a password to open as well.

Is my document or password sent anywhere?

No. Protection is applied on your own computer, and Monstera forgets the password when you close the document.

Full instructions in the Help

• Set a password and permissions
• Open a password-protected PDF

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