This example loads a document called "Temp.doc" and tests to see whether or not it has a digital signature. If there's no digital signature, the example displays a warning message.
Documents.Open _
FileName:="C:\My Documents\Temp.doc"
If ActiveDocument.VBASigned = False Then
MsgBox "Warning! This document " _
& "has not been digitally signed.", _
vbCritical, "Digital Signature Warning"
End If