This application is emulator of the 3-rotor Kriegsmarine M3 Enigma machine, which is used during the World War II. 

The Enigma machine has a series of settings that determines how it encrypts each letter. The settings include rotor wheel position, rotor type, and plug-board settings. 

The settings window can be accessed by holding any of the Up, Select or Down buttons.

On the main screen, the input letter can be shifted by pressing the Up or Down button. The button left circle contains the input text and the upper left circle contains the output text. Pressing the Select button adds the input letter to the input message and the corresponding output letter is added to the output message.