(VB.NET) Examine Client Certificates for an Accepted TLS Connection

Demonstrates how to access the client certificates for a TLS connection accepted by your application acting as the server.

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

Dim listenSslSocket As New Chilkat.Socket

' An SSL/TLS server needs a digital certificate.  This example loads it from a PFX file.
' This is the server's certificate.

Dim cert As New Chilkat.Cert
Dim success As Boolean = cert.LoadPfxFile("qa_data/serverCert/myServerCert.pfx","pfx_password")
If (success <> True) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


' To accept client client certificates in the TLS handshake,
' we must indicate a list of acceptable client certificate root CA DN's
' that are allowed.  (DN is an acronym for Distinguished Name.)
' Call AddSslAcceptableClientCaDn once for each acceptable CA DN.
' Here are a few examples so you can see the general format of a DN.
listenSslSocket.AddSslAcceptableClientCaDn("C=SE, O=AddTrust AB, OU=AddTrust External TTP Network, CN=AddTrust External CA Root")
listenSslSocket.AddSslAcceptableClientCaDn("O=Digital Signature Trust Co., CN=DST Root CA X3")

' Initialize with our server's TLS certificate.
success = listenSslSocket.InitSslServer(cert)
If (success <> True) Then
    Debug.WriteLine(listenSslSocket.LastErrorText)
    Exit Sub
End If


' Bind and listen on a port:
Dim myPort As Integer = 8123
' Allow for a max of 5 queued connect requests.
Dim backLog As Integer = 5
success = listenSslSocket.BindAndListen(myPort,backLog)
If (success <> True) Then
    Debug.WriteLine(listenSslSocket.LastErrorText)
    Exit Sub
End If



' Accept the next incoming connection.
Dim maxWaitMillisec As Integer = 20000
Dim clientSock As Chilkat.Socket = listenSslSocket.AcceptNextConnection(maxWaitMillisec)
If (listenSslSocket.LastMethodSuccess = False) Then
    Debug.WriteLine(listenSslSocket.LastErrorText)
    Exit Sub
End If


' Examine the client certs chain.  The 1st cert will be the client certificate, and
' the subsequent certs will be the certs in the chain of authentication.
Dim numClientCerts As Integer = clientSock.NumReceivedClientCerts
Debug.WriteLine("numClientCerts = " & numClientCerts)

Dim i As Integer = 0
While i < numClientCerts
    Dim clientCert As Chilkat.Cert = clientSock.GetReceivedClientCert(i)
    Debug.WriteLine(clientCert.SubjectDN)

    i = i + 1
End While



' Close the connection with the client
success = clientSock.Close(1000)