(Swift 3,4,5...) Send Signed Email using PFX File (long version)

Demonstrates how to send a signed email using a digital certificate w/ private key stored in a PFX file.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // The mailman object is used for sending and receiving email.
    let mailman = CkoMailMan()!

    // Set the SMTP server.
    mailman.smtpHost = "smtp.mymailserver.com"

    // Create a new email object
    let email = CkoEmail()!

    email.subject = "This email is signed"
    email.body = "This is a digitally signed mail"
    email.from = "Chilkat Admin <admin@chilkatsoft.com>"
    var success: Bool = email.add(to: "Chilkat Support", emailAddress: "support@chilkatsoft.com")

    // Indicate that the email should be sent signed.
    email.sendSigned = true

    // Load a PFX file into a certificate store object.
    // Then locate the certificate matching the  sender's email address,
    // and use it for signing.
    // (a PFX file may contain more than one certificate.)
    let certStore = CkoCertStore()!
    // The 1st argument is the path of the PFX file, the 2nd arg is the 
    // PFX file's password:
    success = certStore.loadPfxFile("/pfx_files/chilkatsoft_secret.pfx", password: "secret")
    if success != true {
        print("\(certStore.lastErrorText!)")
        return
    }

    var cert: CkoCert? = certStore.findCert(bySubjectE: "admin@chilkatsoft.com")
    if certStore.lastMethodSuccess == false {
        print("\(certStore.lastErrorText!)")
        return
    }

    // Alternatively, if a PFX file is known to contain a single certificate,
    // you may load it directly into a Chilkat certificate object.
    // This snippet of source code shows how:
    let cert2 = CkoCert()!
    // The 1st argument is the filename, the 2nd arg is the 
    // PFX file's password:
    success = cert2.loadPfxFile("/pfx_files/chilkatsoft_secret.pfx", password: "secret")
    if success != true {
        print("\(cert2.lastErrorText!)")
        cert = nil
        return
    }

    // This example will use the cert from the certStore...
    success = email.setSigning(cert)

    // Signed email can be sent in two different ways.  
    // In a multipart/signed email, the signature is attached as a separate MIME part.
    // In an opaque email (signedData) the content of the email is encapsulated within the signature
    // and the email is sent as "application/pkcs7-mime". 
    // Either should be fine, but some receiving systems might require one or the other..
    mailman.opaqueSigning = false

    // Send a signed email.
    success = mailman.send(email)
    if success != true {
        print("\(mailman.lastErrorText!)")
    }
    else {
        // The LastErrorText property provides information
        // even when successful.
        print("\(mailman.lastErrorText!)")
        print("Mail Sent!")
    }

    cert = nil

}