How the Enigma Machine works

Find out about how the Enigma works

The enigma machine consists of a series of simple ciphers. It has several components (as seen below) a plug board, a light board, a key board, a set of rotors and a reflector. The original machine looks like a typewriter.

The machine has many variable settings that affect the operation of the machine. The user selects 3 rotors from a set, the tree rotors are place into the machine. A rotor contains one-to-one mappings of all the letters. The plug board allowed for pairs of letters to be remapped before the encryption process started and after it ended.


When a key is pressed, an electrical current is sent through the machine. The current first passes through the plug board, then through the three rotors, through the reflector which reverses the current, back through the three rotors, back through the plug board and then the encrypted letter is lit on the display. After the display is lit up, the rotors rotate. The rotors rotate similar to an odometer where the right most rotor must complete one revolution before the middle rotor rotated one position and so on. As the elctrical current goes through the machine, the letter is remapped into another letter.he plug board performed the first remapping. If there is a connection between two letters, the letters are remapped to each other. For example if there is a connection between "A" and "F", "A" would get remapped to "F" and "F" would get remapped to "A". If this isn't a connection for a particular letter, the letter doesn.t get remapped.



Video

Look at this video on the enigma machine from ohsu teacher on vimeo
The Enigma Machine