Currently, if you PDF a document and added the current Protection features in order to stop it from being converted back to Word. You can actually upload it to many PDF to Word converters on the internet and it will convert the PDF document back to Word without asking for the password. So a better security feature is needed. Especially for company sensitive documents that I want to PDF, protect and stop anyone from converting back to word.
While implementing password protection, Acrobat warns user that ,third party apps may not honor the permissions that are being set on the file. Please open the file in Acrobat/Reader itself to honor the permissions.
Or you can protect the document with certificate .