Possibly the one or other who is skilled in history, knows of the Enigma. It was a sort of type writing machine used in World War II to encrypt and decrypt messages. EnigmaNDS by mincemeatteam is a virtual Enigma machine for NDS.

Thanks to http://www.nintendomax.com/viewtopic.php?t=13613&f=19 for the news.

http://nds.scenebeta.com/noticia/enigmands