This example loads a presentation called MyPres.ppt and tests to see whether or not it has a digital signature. If there's no digital signature, the code displays a warning message.
Presentations.Open FileName:="c:\My Documents\MyPres.ppt", _
ReadOnly:=False, WithWindow:=msoTrue
With ActivePresentation
If .VBASigned = False And _
.VBProject.VBComponents.Count > 0 Then
MsgBox "Warning! The Visual Basic project for" _
& vbCrLf & "this presentation has not" _
& vbCrLf & " been digitally signed." _
, vbCritical, "Digital Signature Warning"
End If
End With