Identifying protected files

Hi everyone. I have a folder with a large number of PDFs (in the 1000s). We encountered one file that had some password protection - not required to open the file, just for some functionalities. If I look at the Document Properties Security tab, I can see that the selected Security Method is Password Security instead of No Security, and some functions in the Document Restrictions Summary show as Not Allowed.

The task now is to identify other files with password protection, without a human opening each individual one and looking at the doc properties. I'm pretty limited in the tools I can use - just VBA and Python. (I don't have privileges to install anything else.) I do have the PDFMaker Office add-in, but so far I haven't been able to determine how to use that to tap into those document properties. To now I've only used the add-in to combine multiple PDF files to a single file, and that is using borrowed code. So my knowledge of how to use the add-in is close to nothing, and I haven't yet found helpful documentation online.

Thank you for any ideas.