PDF security settings

I would like to be able to tell which PDFs have security settings set (without having to open each PDF to check).

Is it possible to do this is DOpus?

The metadata pane does not have a specific "security" field displayed. However it appears to be the case that if security is set then all the Document Properties (Authors, Creator, Producer, Subject, Title) in the metadata pane always appear blank (even when they are not in fact blank) so this may be a way of (indirectly) telling whether security is set or not. I'm not sure whether this is by accident or design.