(VB.NET) Get the Server Certificate, Certificate Chain, and Root CA Certificate

Demonstrates how to get the HTTP server certificate, its certificate chain, and the root CA certificate.

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' This example assumes the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim http As New Chilkat.Http

' We're getting the SSL/TLS certificate, so make sure to connect to the SSL/TLS port (443).
Dim sslCert As Chilkat.Cert = http.GetServerSslCert("nationalgeographic.com",443)
If (http.LastMethodSuccess = False) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


' Note: Prior to v9.5.0.50, this method would fail if the certificate chain could not 
' be completed to the root.  Starting in v9.5.0.50, the incomplete certificate chain 
' will be returned.  The certificate chain's ReachesRoot property can be examined to 
' see if the chain was completed to the root.
Dim certChain As Chilkat.CertChain = sslCert.GetCertChain()
If (sslCert.LastMethodSuccess = False) Then
    Debug.WriteLine(sslCert.LastErrorText)

    Exit Sub
End If


Dim i As Integer = 0
Dim numCerts As Integer = certChain.NumCerts
While i < numCerts
    Dim cert As Chilkat.Cert = certChain.GetCert(i)
    Debug.WriteLine("SubjectDN " & i & ": " & cert.SubjectDN)
    Debug.WriteLine("IssuerDN " & i & ": " & cert.IssuerDN)

    i = i + 1
End While

' If the certificate chain reaches the root CA cert, then the last cert in the chain
' is the root CA cert.
If (certChain.ReachesRoot = True) Then
    Dim caCert As Chilkat.Cert = certChain.GetCert(numCerts - 1)
    Debug.WriteLine("CA Root Cert: " & caCert.SubjectDN)

End If