What is a valid digital certificate for a file?

Hi.
When I checked the digital certificate for file "EXCEL.EXE", I saw
"Valid from 3/29/01 to 5/29/02".
Today is 7/14/2004.
If it is a certificate on Apache server, it will say "This certificate
has expired."
But Windows told me "This certificate is OK."
How can it be possible to be OK?
After I renamed the file "EXCEL.EXE" to "EXCEL123.EXE", it still says
"This certificate is OK."
The certificate protects software from alteration after publication.
If the filename is changed, is that an alteration?
If I signed a DLL with a certificate and renamed it, the DLL file's
certificate will be OK, but there is no way to use it as before.
Please let me know the true meaning of digital certificate.
Thank you,

Jorge
Thu Jul 15 14:54:14 CDT 2004

I hope this helps
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/SP_AMO/html/howHowToCreateCertificatesForBinaryFileSigning.asp
Thanks
JC

--
This posting is provided "AS IS" with no warranties, and confers no rights

"Frank Meng" <mengfrank@hotmail.com> wrote in message
news:1a370138.0407141844.333f16dd@posting.google.com...
> Hi.
> When I checked the digital certificate for file "EXCEL.EXE", I saw
> "Valid from 3/29/01 to 5/29/02".
> Today is 7/14/2004.
> If it is a certificate on Apache server, it will say "This certificate
> has expired."
> But Windows told me "This certificate is OK."
> How can it be possible to be OK?
> After I renamed the file "EXCEL.EXE" to "EXCEL123.EXE", it still says
> "This certificate is OK."
> The certificate protects software from alteration after publication.
> If the filename is changed, is that an alteration?
> If I signed a DLL with a certificate and renamed it, the DLL file's
> certificate will be OK, but there is no way to use it as before.
> Please let me know the true meaning of digital certificate.
> Thank you,