Why can't a user add a certified signature to a secured PDF?

[elainer38412449]

Users who are using a form I create aren't able to add a certified signature whenever I add 'Protect > Secure with Password to the PDF. How can I allow them to add their certified signatures? I have added the fields and specified the type as 'Signature Blocks' to no avail.

[Nancy OShea]

Right.  "Protect" essentially locks the document which is fine for Read Only files.  But documents requiring signature are not Read Only files are they?

https://helpx.adobe.com/acrobat/using/securing-pdfs-passwords.html

[margueritek]

You can't add a Certifying signature after protecting with password, but you can Certify at the same time as you add password protection (same Save step)

[margueritek]

Actually, you can Certify after saving with a password. I just tried it with a visible signature in a previously authored signature field. Make sure your protection allows signing with digital signatures.