A simple enigma
Early a century after its invention, the electromechanical Enigma cipher machine still strikes a deep chord among the digerati. Used by the German military to encode communications in the run-up to and during World War II, the Enigma has achieved a mythic quality in computing history-the Medusa slain by the hero Turing with the new weapon of digital logic. Consequently, original Enigma machines are now collector's items that sell for tens of thousands of dollars. Even replicas are pricey. So the only alternative for those wishing to get to grips with this machine-and to better understand the mathematical, engineering, and operational feats that defeated it-has been to use one of a number of software emulators. But now there's a middle ground: a hardware kit that duplicates the physical operation of the Enigma's keyboard, display, and plugboard while replacing the rotating metal discs at the machine's heart with an Arduino Mega microcontroller.