VBASigned Property [Excel 2003 VBA Language Reference]
True if the Visual Basic for Applications project for the specified workbook has been digitally signed. Read-only Boolean.
This example loads a workbook named "mybook.xls" and then tests to see whether its Visual Basic for Applications project has a digital signature. If there's no digital signature, the example displays a warning message.
Workbooks.Open FileName:="c:\My Documents\mybook.xls", _ ReadOnly:=False If Workbook.VBASigned = False Then MsgBox "Warning! The project " _ "has not been digitally signed." _ , vbCritical, "Digital Signature Warning" End If