The mechanical subsystem consists of a keyboard; a set of rotating disks called rotors arranged adjacently along a spindle; and one of various stepping components to turn at least one rotor with each key press.
Enigma wiring diagram with arrows and the numbers 1 to 9 showing how current flows from key depression to a lamp being lit. D yields A, but A never yields A; this property was due to a patented feature unique to the Enigmas, and could be exploited by cryptanalysts in some situations.
When the rotors were mounted side-by-side on the spindle, the pins of one rotor rested against the plate contacts of the neighbouring rotor, forming an electrical connection.
Inside the body of the rotor, 26 wires connected each pin on one side to a contact on the other in a complex pattern.
In 1938, the Germans added complexity to the Enigma machines that finally became too expensive for the Poles to counter.
The Poles had six bomby, but when the Germans added two more rotors, ten times as many bomby were needed, but the Poles did not have the resources.
The Enigma machines were a series of electro-mechanical rotor cipher machines developed and used in the early- to mid-twentieth century to protect commercial, diplomatic and military communication.
Enigma was invented by the German engineer Arthur Scherbius at the end of World War I.
in Pyry near Warsaw, the Poles initiated French and British military intelligence representatives into their Enigma-decryption techniques and equipment, including Zygalski sheets and the cryptologic bomb, and promised each delegation a Polish-reconstructed Enigma.
The demonstration represented a vital basis for the later British continuation and effort.
The mechanical parts act in such a way as to form a varying electrical circuit.
When a key is pressed, one or more rotors move to form a new rotor configuration, and a circuit is completed.
The letter A encrypts differently with consecutive key presses, first to G, and then to C.