(Swift 3,4,5...) POP3 Verify Signed (S/MIME) Email

Demonstrates how to download and verify digitally signed S/MIME email.

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.

    let mailman = CkoMailMan()!
    var success: Bool

    // Set the POP3 server's hostname
    mailman.mailHost = "pop.someMailServer.com"

    // Set the POP3 login/password.
    mailman.popUsername = "myLogin"
    mailman.popPassword = "myPassword"

    var sa: CkoStringArray? = mailman.getUidls()
    if mailman.lastMethodSuccess == false {
        print("\(mailman.lastErrorText!)")
        return
    }

    var email: CkoEmail?
    var uidl: String?

    var i: Int = 0
    while i < sa!.count.intValue {

        uidl = sa!.getString(i)

        email = mailman.fetchEmail(uidl)
        if mailman.lastMethodSuccess == false {
            print("\(mailman.lastErrorText!)")
            sa = nil
            return
        }

        print("\(email!.from!)")
        print("\(email!.subject!)")

        // The security layers of signed and/or encrypted emails
        // are automatically "unwrapped" when loaded into
        // a Chilkat email object.
        // An application only needs to check to see if an email
        // was received signed or encrypted, and then examine
        // the success/failure.  For example:
        if email!.receivedSigned == true {

            print("This email was signed.")

            // Check to see if the signatures were verified.
            if email!.signaturesValid == true {
                print("Digital signature(s) verified.")
                print("Signer: \(email!.signedBy!)")

                // The certificate used for signing may be obtained
                // by calling email.GetSignedByCert.
                var cert: CkoCert?
                cert = email!.getSignedByCert()
                if email!.lastMethodSuccess == false {
                    print("Failed to get signing certificate object.")
                }
                else {
                    print("Signing cert: \(cert!.subjectCN!)")
                    cert = nil
                }

            }
            else {
                print("Digital signature verification failed.")
            }

        }

        email = nil
        i = i + 1
    }

    sa = nil

    mailman.pop3EndSession()

}