Android™

Use a TLS Client Certificate

Demonstrates the Chilkat MailMan.SetSslClientCert method, which sets the client-side certificate to use for SSL/TLS connections. This is typically not required — most SSL/TLS connections authenticate the server only. This example loads a client certificate from a PFX and uses it when connecting.

Background: In an ordinary TLS handshake only the server presents a certificate, and the client proves who it is later with a password. Mutual TLS adds a second leg: the client also presents a certificate, so it is authenticated cryptographically at the transport layer. Some corporate or high-security mail servers require this. Because the client must prove possession of the key, the certificate needs its private key — hence loading from a PFX.

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Android™

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    //  Demonstrates the MailMan.SetSslClientCert method, which sets the client-side certificate
    //  to use for SSL/TLS connections.  This is typically not required -- most SSL/TLS
    //  connections authenticate the server only.

    CkMailMan mailman = new CkMailMan();

    //  Configure the SMTP server connection.
    mailman.put_SmtpHost("smtp.example.com");
    mailman.put_SmtpPort(465);
    mailman.put_SmtpSsl(true);
    mailman.put_SmtpUsername("user@example.com");
    mailman.put_SmtpPassword("myPassword");

    //  Load the client certificate (with its private key) from a PFX file.
    CkCert cert = new CkCert();
    success = cert.LoadPfxFile("qa_data/certs/client.pfx","pfx_password");
    if (success == false) {
        Log.i(TAG, cert.lastErrorText());
        return;
        }

    //  Use this certificate to identify the client during the TLS handshake.
    success = mailman.SetSslClientCert(cert);
    if (success == false) {
        Log.i(TAG, mailman.lastErrorText());
        return;
        }

    success = mailman.VerifySmtpLogin();
    if (success == false) {
        Log.i(TAG, mailman.lastErrorText());
        return;
        }

    Log.i(TAG, "Connected using a TLS client certificate.");

    //  Note: The path "qa_data/certs/client.pfx" is a relative local filesystem path,
    //  relative to the current working directory of the running application.

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}