WinAuth 2 Way Authentication provides you with a second layer of security for your Windows login screen.Once you finish the simple set up, you will only be able to unlock Windows via the secret password and USB Key. You can also use it in conjunction with the Android app by scanning a barcode through the WinAuth Unlock Client. WinAuth 2 Way Authentication is a nice melding of Windows and Android to provide security for your machine and the fact that it simple to use and free are just bonuses.