Swift

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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Swift


func chilkatTest() {
    var success: Bool = 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 = CkoMailMan()!

    //  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.
    let cert = CkoCert()!
    success = cert.loadPfxFile(path: "qa_data/certs/client.pfx", password: "pfx_password")
    if success == false {
        print("\(cert.lastErrorText!)")
        return
    }

    //  Use this certificate to identify the client during the TLS handshake.
    success = mailman.setSslClientCert(cert: cert)
    if success == false {
        print("\(mailman.lastErrorText!)")
        return
    }

    success = mailman.verifySmtpLogin()
    if success == false {
        print("\(mailman.lastErrorText!)")
        return
    }

    print("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.

}