Java

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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Chilkat2 Java

import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.MailMan;

public class ChilkatExample {

    public static void main(String[] args) {
        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.

        MailMan mailman = new MailMan();

        // Configure the SMTP server connection.
        mailman.setSmtpHost("smtp.example.com");
        mailman.setSmtpPort(465);
        mailman.setSmtpSsl(true);
        mailman.setSmtpUsername("user@example.com");
        mailman.setSmtpPassword("myPassword");

        // Load the client certificate (with its private key) from a PFX file.
        Cert cert = new Cert();
        try {
            cert.loadPfxFile("qa_data/certs/client.pfx", "pfx_password");

            // Use this certificate to identify the client during the TLS handshake.
            mailman.setSslClientCert(cert);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        success = mailman.verifySmtpLogin();
        if (!success) {
            System.out.println(mailman.getLastErrorText());
            return;
        }

        System.out.println("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.
    }
}