PHP

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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<?php

use Chilkat2\Cert;
use Chilkat2\MailMan;

$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 = new MailMan();

// Configure the SMTP server connection.
$mailman->SmtpHost = 'smtp.example.com';
$mailman->SmtpPort = 465;
$mailman->SmtpSsl = true;
$mailman->SmtpUsername = 'user@example.com';
$mailman->SmtpPassword = 'myPassword';

// Load the client certificate (with its private key) from a PFX file.
$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 (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

$success = $mailman->VerifySmtpLogin();
if (!$success) {
    echo $mailman->LastErrorText, "\n";
    exit;
}

echo "Connected using a TLS client certificate.\n";

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