(Xojo Plugin) 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.

Chilkat Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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
success = cert.LoadPfxFile("qa_data/serverCert/myServerCert.pfx","pfx_password")
If (success <> True) Then
    System.DebugLog(cert.LastErrorText)
    Return
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 <> True) Then
    System.DebugLog(listenSslSocket.LastErrorText)
    Return
End If

// Bind and listen on a port:
Dim myPort As Int32
myPort = 8123
// Allow for a max of 5 queued connect requests.
Dim backLog As Int32
backLog = 5
success = listenSslSocket.BindAndListen(myPort,backLog)
If (success <> True) Then
    System.DebugLog(listenSslSocket.LastErrorText)
    Return
End If

// Accept the next incoming connection.
Dim maxWaitMillisec As Int32
maxWaitMillisec = 20000
Dim clientSock As Chilkat.Socket
clientSock = listenSslSocket.AcceptNextConnection(maxWaitMillisec)
If (listenSslSocket.LastMethodSuccess = False) Then
    System.DebugLog(listenSslSocket.LastErrorText)
    Return
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 Int32
numClientCerts = clientSock.NumReceivedClientCerts
System.DebugLog("numClientCerts = " + Str(numClientCerts))

Dim i As Int32
i = 0
While i < numClientCerts
    Dim clientCert As Chilkat.Cert
    clientCert = clientSock.GetReceivedClientCert(i)
    System.DebugLog(clientCert.SubjectDN)

    i = i + 1
Wend

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