B4X Requires Chilkat v11.0.0+

Accept TLS Connection with Client Authentication

See more Socket/SSL/TLS Examples

Demonstrates how to accept a TLS connection requiring client authentication. This is the case where the TLS client sends a certificate. It is also known as "Two-Way SSL". B4X

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 ChilkatSocket
listenSslSocket.Initialize("listenSslSocket")

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

Dim cert As ChilkatCert
cert.Initialize("cert")
'  The 1st argument is the file path, the 2nd arg is the 
'  PFX file's password:
success = cert.LoadPfxFile("chilkat.pfx", "test")
If success = False Then
    Log(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.
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")

'  Use the certificate:
success = listenSslSocket.InitSslServer(cert)
If success = False Then
    Log(listenSslSocket.LastErrorText)
    Return
End If


'  Bind and listen on a port:
Dim myPort As Int = 8123
'  Allow for a max of 5 queued connect requests.
Dim backLog As Int = 5
success = listenSslSocket.BindAndListen(myPort, backLog)
If success = False Then
    Log(listenSslSocket.LastErrorText)
    Return
End If


'  If accepting an SSL/TLS connection, the SSL handshake is part of the connection
'  establishment process. This involves a few back-and-forth messages between the 
'  client and server to establish algorithms and a shared key to create the secure 
'  channel. The sending and receiving of these messages are governed by the 
'  MaxReadIdleMs and MaxSendIdleMs properties. If these properties are set to 0 
'  (and this is the default unless changed by your application), then the 
'  AcceptNext can hang indefinitely during the SSL handshake process. 
'  Make sure these properties are set to appropriate values before calling AcceptNext.

'  Set a 10 second max for waiting to read/write.  This is for the SSL/TLS handshake establishment.
listenSslSocket.MaxReadIdleMs = 10000
listenSslSocket.MaxSendIdleMs = 10000

'  Accept a single client connection and establish the secure SSL/TLS channel:
Dim maxWaitMillisec As Int = 20000
Dim clientSock As ChilkatSocket
clientSock.Initialize("clientSock")
success = listenSslSocket.AcceptNext(maxWaitMillisec, clientSock)
If success = False Then
    Log(listenSslSocket.LastErrorText)
    Return
End If


'  The client (in this example) is going to send a "Hello Server! -EOM-" 
'  message.  Read it:
Dim receivedMsg As String = clientSock.ReceiveUntilMatch("-EOM-")
If clientSock.LastMethodSuccess = False Then
    Log(clientSock.LastErrorText)
    Return
End If


Log(receivedMsg)

'  Send a "Hello Client! -EOM-" message:
success = clientSock.SendString("Hello Client! -EOM-")
If success = False Then
    Log(clientSock.LastErrorText)
    Return
End If


'  Close the connection with the client
'  Wait a max of 20 seconds (20000 millsec)
success = clientSock.Close(20000)