如何通過聽寫在手錶應用程序中輸入信用卡的安全CVV號碼？

我必須通過聽寫在手錶OS2 sdk上設計的手錶應用程序中輸入信用卡的CVV號碼。但是號碼正在按原樣打印。不是安全的密鑰。如何通過聽寫在手錶應用程序中輸入信用卡的安全CVV號碼？

let textChoices = ["123","124","236","456", "345", "Seriously, just order Pizza!!"] 
    presentTextInputControllerWithSuggestions(textChoices, 
     allowedInputMode: WKTextInputMode.Plain, 
     completion: {(results) -> Void in 
      if results != nil && results!.count > 0 { //selection made 
       let aResult = results?[0] as? String 
        self.labelPrint.setText(aResult) 


        //{ 
        //self.labelPrint.setText(aResult) 
       //} 
      }})

任何人都可以建議如何使輸入的數字作爲安全密鑰？

感謝

來源

2015-12-09 Sami Karn