Utility to Find Password Protected Files

[Guest]

I want to make a list of the documents (Word & Excel)
that are on our network which are passworded in order to
ensure that we have the passwords in our vault.

I thought I could use the Search function in advanced
mode but there is no attribute for Password.

I thought maybe since password protected files are not
indexed I could utilize that somehow as a trigger.

Anyone ever found a utility or method that does this?

Thanks - Randy