Rust

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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Rust

let mut 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.

let mailman = chilkat::MailMan::new();

// Configure the SMTP server connection.
mailman.set_smtp_host("smtp.example.com");
mailman.set_smtp_port(465);
mailman.set_smtp_ssl(true);
mailman.set_smtp_username("user@example.com");
mailman.set_smtp_password("myPassword");

// Load the client certificate (with its private key) from a PFX file.
let cert = chilkat::Cert::new();
if cert.load_pfx_file("qa_data/certs/client.pfx", "pfx_password").is_err() {
    println!("{}", cert.last_error_text());
    return;
}

// Use this certificate to identify the client during the TLS handshake.
if mailman.set_ssl_client_cert(&cert).is_err() {
    println!("{}", mailman.last_error_text());
    return;
}

success = mailman.verify_smtp_login();
if !success {
    println!("{}", mailman.last_error_text());
    return;
}

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.