Certificate parsing with C#
Back in year 2000 I started using ASP and the
"Request.ClientCertificate Collection" described at
Link to an old ASP page behind the login requirement of this site -
At that time I thought I was really cool doing smart card logon to a web site
with certificate parsing. Back in those days anyone who could spell "smart card"
had a lot of marked attention.
But at the same time Windows 2000 was released (launched to retail on 17
February 2000) introducing "Smart Card Logon" to Windows itself. But that
feature intruduced the certificate field "Subject Alternative Name" containing
UPN for the certificate holder, for example "firstname.lastname@example.org". I thought
spelling out the name of an application in the certificates was a horrible thing
to do (company.com is the name of the "application" Active Directory within
However, Microsoft didn't listen and I wanted to parse "UPN" from the
certificate in my ASP code. But since I'm just a copy-paste-programmer I never
figured out how to do it with
Guess it's not supported and the conversion from the binary format retreived
with "RequestClientCertificate("Certificate") was not that easy.
But now with some C# I finally got it working: