(Java) 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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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkSocket listenSslSocket = new CkSocket();

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

    CkCert cert = new CkCert();
    boolean success = cert.LoadPfxFile("qa_data/serverCert/myServerCert.pfx","pfx_password");
    if (success != true) {
        System.out.println(cert.lastErrorText());
        return;
        }

    // 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) {
        System.out.println(listenSslSocket.lastErrorText());
        return;
        }

    // Bind and listen on a port:
    int myPort = 8123;
    // Allow for a max of 5 queued connect requests.
    int backLog = 5;
    success = listenSslSocket.BindAndListen(myPort,backLog);
    if (success != true) {
        System.out.println(listenSslSocket.lastErrorText());
        return;
        }

    // Accept the next incoming connection.
    int maxWaitMillisec = 20000;
    CkSocket clientSock = listenSslSocket.AcceptNextConnection(maxWaitMillisec);
    if (listenSslSocket.get_LastMethodSuccess() == false) {
        System.out.println(listenSslSocket.lastErrorText());
        return;
        }

    // 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.
    int numClientCerts = clientSock.get_NumReceivedClientCerts();
    System.out.println("numClientCerts = " + numClientCerts);

    int i = 0;
    while (i < numClientCerts) {
        CkCert clientCert = clientSock.GetReceivedClientCert(i);
        System.out.println(clientCert.subjectDN());

        i = i+1;
        }

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