Starter Questions on Authenticode

Question

Hi,

I'm trying to uniquely identify a Windows Application.

And I've found out tthat authenticode is a way to uniquely identify a Windows Application, and is useful to find out if an application is one written by an untrusted developer.

And I've read that Authenticode is a signature mechanism.

Here's a few starter questions on Authenticode:

To verify the Authenticode signature of a Windows Application, what input data do I need? Such as the encrypted data, the signature, etc, and how about their data type, are they arrays of bytes?

And having got the input, are there ready functions to verify that? .NET classes are highly preferred, if there aren't ones ready, I'll consider using P/Invoke to use native functions.

Buy the way, is the signature and encrypted data retrievable by other applications?

Thanks a lot.