(VB.NET) Get Certificate User Principal Name (UPN)

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Demonstrates how to get a certificate's UPN from the SAN (Subject Alternative Name). Most certificates do not have a UPN. This example only applies to those certificates that have a User Principal Name.

Note: This example requires Chilkat v9.5.0.90 or greater due to fixes made in getting the UPN from the SAN.

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Dim cert As New Chilkat.Cert

Dim success As Boolean = cert.LoadFromFile("qa_data/certs/sample.cer")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


Dim xml As New Chilkat.Xml
xml.LoadXml(cert.SubjectAlternativeName)
Debug.WriteLine(xml.GetXml())

' A certificate with a User Principal Name in the SAN might have this:

' <SubjectAltName>
'     <rfc822Name>joe@example.com</rfc822Name>
'     <name type="oid" oid="1.3.6.1.4.1.311.20.2.3">joe@example.com</name>
' </SubjectAltName>

' The OID 1.3.6.1.4.1.311.20.2.3 is for the User Principal Name.
Dim upn As String = xml.ChilkatPath("/A/name,oid,1.3.6.1.4.1.311.20.2.3|*")
If (xml.LastMethodSuccess = False) Then
    Debug.WriteLine("No user principle name.")
Else
    Debug.WriteLine("User Principle Name = " & upn)
End If