Hi Don The certificate is for adding to VBA Projects and once selected clicking save in VBA Window will activate aslong as you have chosed the correct certificate that you have the private key for. If you want to protect the document contents from changing this is different it is in tools options security and works in a similar fashion it needs a saved document to make a hash from and then stores the certificate info, this works fine on my office 2003 showing in the title bar [Signed, verified or unverified] Hope this helps Mike Walker (Reply via NG) it attached to my Excel applications. of attaching it. However, it does not really attach to the application. The next time the application is opened, the certificate is not there. certificate does not even appear as being available to be added. setting that is needed somewhere in the computer, or is it something to do with Excel.