Is possible open and read sharepoint list item attachment like Package.Open method?

Question

I need to open and read sharepoint list item attachment like "Package.Open" method.

Actually, I'm using Package.Open method to open/read a document locally and the method return the opened package.

Then using "PackageDigitalSignatureManager" I check if the document have signature (below is the code I am using)

Now, I need check the documents of SharePoint list item attachment, is possible do that?