   static function encrypt($string, $key) {

      $result = '';
      for ($i=0; $i<strlen($string); $i++) {
         $char    = substr($string, $i, 1);
         $keychar = substr($key, ($i % strlen($key))-1, 1);
         $char    = chr(ord($char)+ord($keychar));
         $result .= $char;
      }
      return base64_encode($result);
   }
The software contains hard-coded credentials, such as a password or cryptographic key, which it uses for its own inbound authentication, outbound communication to external components, or encryption of internal data.