VB.NET

Examine Client Certificates for an Accepted TLS Connection

See more Socket/SSL/TLS Examples

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

Dim success As Boolean = False

' 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
success = cert.LoadPfxFile("qa_data/serverCert/myServerCert.pfx","pfx_password")
If (success = False) 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 = False) 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 = False) Then
    Debug.WriteLine(listenSslSocket.LastErrorText)
    Exit Sub
End If


' Accept the next incoming connection.
Dim maxWaitMillisec As Integer = 20000

Dim clientSock As New Chilkat.Socket
success = listenSslSocket.AcceptNext(maxWaitMillisec,clientSock)
If (success = 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 clientCert As New Chilkat.Cert
Dim i As Integer = 0
While i < numClientCerts
    clientSock.GetRcvdClientCert(i,clientCert)
    Debug.WriteLine(clientCert.SubjectDN)
    i = i + 1
End While

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