// initial a "SAPinViewController" via the designate initialiser
let pinVC = SAPinViewController(withDelegate: self, backgroundImage: UIImage(named: "bg3"))
// setup different properties
pinVC.subtitleText = "Your passcode is required to enable Touch ID"
pinVC.buttonBorderColor = UIColor.whiteColor()
pinVC.alphabetColor = UIColor.whiteColor()
pinVC.showAlphabet = true // default is true
// ... and other properties
// present it
presentViewController(pinVC, animated: true, completion: nil)
// implement delegate methods
extension ViewController: SAPinViewControllerDelegate {
    func pinEntryWasCancelled() {
        dismissViewControllerAnimated(true, completion: nil)
    }
    func pinEntryWasSuccessful() {
        dismissViewControllerAnimated(true, completion: nil)
    }
    func pinWasIncorrect() {

    }
    func isPinValid(pin: String) -> Bool {
        return pin == pinString
    }
}