Classic ASP Requires Chilkat v11.0.0+
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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<%
success = 0

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

set listenSslSocket = Server.CreateObject("Chilkat.Socket")

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

set cert = Server.CreateObject("Chilkat.Cert")
success = cert.LoadPfxFile("qa_data/serverCert/myServerCert.pfx","pfx_password")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( cert.LastErrorText) & "</pre>"
    Response.End
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.
success = listenSslSocket.AddSslAcceptableClientCaDn("C=SE, O=AddTrust AB, OU=AddTrust External TTP Network, CN=AddTrust External CA Root")
success = 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 = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( listenSslSocket.LastErrorText) & "</pre>"
    Response.End
End If

'  Bind and listen on a port:
myPort = 8123
'  Allow for a max of 5 queued connect requests.
backLog = 5
success = listenSslSocket.BindAndListen(myPort,backLog)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( listenSslSocket.LastErrorText) & "</pre>"
    Response.End
End If

'  Accept the next incoming connection.
maxWaitMillisec = 20000

set clientSock = Server.CreateObject("Chilkat.Socket")
success = listenSslSocket.AcceptNext(maxWaitMillisec,clientSock)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( listenSslSocket.LastErrorText) & "</pre>"
    Response.End
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.
numClientCerts = clientSock.NumReceivedClientCerts
Response.Write "<pre>" & Server.HTMLEncode( "numClientCerts = " & numClientCerts) & "</pre>"

set clientCert = Server.CreateObject("Chilkat.Cert")
i = 0
Do While i < numClientCerts
    success = clientSock.GetRcvdClientCert(i,clientCert)
    Response.Write "<pre>" & Server.HTMLEncode( clientCert.SubjectDN) & "</pre>"
    i = i + 1
Loop

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

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