Key : Your Smartphone as a credential: With the “Key” app from Interflex, you can open doors using your smartphone. This is how "Key" works: - Install the "Key" app on your smartphone. - Log in with your user name and password. - Identify yourself with your smartphone at the access control terminal. This app requires use of the Interflex IF-6040 software and of the adequate readers. We guarantee encrypted and secure transmission of the mobile key to your smartphone.