Password protect attachments


I note if you attach a password protected PDF to a base on both desktop and iOS if you try to access the file it asks for your password and opens. The same however is not true for docx files you need to download the file out of airtable then open it with the password. This raises 2 questions for me is there any way docx that are password protected can be opened within airtable. Secondly I have bases with pdf attachments is there any way I can password protect the files within airtable ie can I password protect a whole field or must I individually replace the pdf files with password protected ones?