(Swift) POP3 Verify Signed (S/MIME) Email

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

Note: This example requires Chilkat v11.0.0 or greater.

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

func chilkatTest() {
    var success: Bool = false

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

    let mailman = CkoMailMan()!

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

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

    let stUidls = CkoStringTable()!
    success = mailman.fetchUidls(stUidls)
    if success == false {
        print("\(mailman.lastErrorText!)")
        return
    }

    let email = CkoEmail()!
    let cert = CkoCert()!

    var count: Int = stUidls.count.intValue
    var i: Int = 0
    while i < count {
        // Download the full email.
        success = mailman.fetch(byUidl: stUidls.string(at: i), headerOnly: false, numBodyLines: 0, email: email)
        if success == false {
            print("\(mailman.lastErrorText!)")
            return
        }

        print("\(i)")
        print("From: \(email.from!)")
        print("Subject: \(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!)")

                success = email.lastSignerCert(0, cert: cert)
                if success == false {
                    print("\(email.lastErrorText!)")
                    return
                }

                print("Signing cert: \(cert.subjectCN!)")
            }

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

        i = i + 1
    }

    mailman.pop3EndSession()

}