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| This article is the part of the series on the Enigma cipher machine. |
| Enigma machine |
| Cryptanalysis of the Enigma |
| Perforated sheets |
| Bomba |
| Bombe |
| Ultra |
In the history of cryptography, the Enigma was a portable cipher machine used to encrypt and decrypt secret messages. More precisely, Enigma was a family of related electro-mechanical rotor machines there were a variety of different models.
The Enigma was used commercially from the early 1920s on, and was also adopted by the military and governmental services of a number of nations most famously, by Nazi Germany before and during World War II (WWII). The German military model, the Wehrmacht Enigma, is the version most commonly discussed. The machine has gained notoriety because Polish and later Allied codebreakers were able to decrypt a large number of messages that were protected by the machine before being broadcast by radio (see cryptanalysis of the Enigma). The intelligence gained through this source codenamed ULTRA was a significant aid to the Allied war effort. Some historians have suggested that the end of the European warVictory in Europe Day V-E Day was May 8, 1945, the date when the Allies during the Second World War formally celebrated the defeat of Nazi Germany and the end of Adolf Hitler's Reich. On that date, massive celebrations took place, notably in London, where was hastened by up to a year or more because of the decryption of German ciphers.
Figure 1. A three-rotor German military Enigma machine showing, from bottom to top, the plugboard, the keyboard, the lamps and the finger-wheels of the rotors emerging from the inner lid. Although the Enigma cipher has cryptographic weaknesses, it was, in practice, only their combination with other significant factors which allowed codebreakers to read messages: captured machines and codebookJoseph Hookers code clerk In cryptography, a codebook is a document for implementing a code. A codebook contains a lookup table for coding and decoding; each word or phrase has (one or more) strings which replace it. To decipher messages written in code,s, mistakes by operators, and procedural flaws.
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Like other rotor machines, the Enigma machine is a combination of mechanical and electrical systems. The mechanical mechanism consists of a keyboardA keyboard is a data entry or control device using a number of keys which are to be pressed by the fingers. There are two main types of keyboard: Alphanumeric keyboards (including the typewriter keyboard, the generic computer keyboard and its descendant t; a set of rotating disks called rotors arranged adjacently along a spindleA spindle (sometimes called a drop spindle is a wooden spike weighted at one end with a wheel and an optional hook at the other end. It is used for spinning wool and other fibres into thread. Spindles or parts of them have been found in very, very old arc; and a stepping mechanism to turn some of the rotors with each key press. The exact mechanism varies, but the most common form is for the right-hand rotor to step once with every key stroke, and occasionally the motion of neighbouring rotors is triggered. The continual movement of the rotors results in a different cryptographic transformation after each key press.
The mechanical parts act in such a way as to form a varying electrical circuit the actual encipherment of a letter is performed electrically. When a key is pressed, the circuit is completed; current flows through the various components and ultimately lights one of many lampLamp: See Lighting. LAMP: L inux, A pache, M ySQL, P erl, P HP, and/or P ython a popular web server combination.s, indicating the output letter. For example, when encrypting a message starting ANX..., the operator would first press the A key, and the Z lamp might light; Z would be the first letter of the ciphertext. The operator would then proceed to encipher N in the same fashion, and so on.
Current flows from a batteryIn science and technology, a battery is a device that stores energy and makes it available in an electrical form. Although such storage in an electrostatic form is practical in some specialized uses, batteries usually consist of electrochemical devices su through the switchThis article is about electrical switches. For other meanings of the word "switch", see Switch (disambiguation). A switch is a device for making or breaking an electric circuit, or for selecting between multiple circuits. In the simplest case, a switch ha controlled by the depressed key into a fixed entry wheel. This leads into the rotor assembly (or scrambler), where the complex internal wiring of each rotor results in the current passing from one rotor to the next along a convoluted path. After passing through all the rotors, current enters the reflector, which relays the signal back out again through the rotors and the entry wheel this time via a different path and, finally, to one of the lamps (the earliest Enigma models do not have the reflector). In addition, some machines are equipped with a plugboard, which allow the connections between the keyboard and the entry wheel to be easily rewired by an operator.
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