Enigma (machine) Facts for Kids

Military Enigma machine

Three rotors of an enigma machine

The Enigma machine was created for Germany by Arthur Scherbius in World War II. It is a cypher machine: a way of changing the letters of a message so that it appears to be scrambled letters (or, random letters).

Each time a letter is typed, it appears as another letter in the alphabet. The choices are not random. They are decided by a series of rotors which are set each day to a different starting set-up. Every press of a key turns the rotors to a new position.

German military messages done on the Enigma machine were first broken by the Polish Cipher Bureau, beginning in December 1932. Later, they designed mechanical devices for breaking Enigma cyphers. From 1938 more complexity was added to the Enigma machines, making decryption more difficult.

On 25 July 1939, in Warsaw, the Poles showed French and British intelligence agents their cryptanalysis of the Enigma, and promised each delegation a Polish-built Enigma. The demonstration was a vital start for the later British work at Bletchley Park.

"Hut 6 Ultra would never have got off the ground if we had not learned from the Poles, in the nick of time, the details both of the German military version of the commercial Enigma machine, and of the operating procedures that were in use". Gordon Welchman, The Hut Six Story, 1982, p. 289.

Later, the Germans improved their encryption. A new code-breaking group known as "Ultra", led by the English mathematician Alan Turing, was summoned. He developed a more advanced machine that was deciphering naval Enigma messages by 1940. British codebreakers solved a vast number of messages from Enigma, and gave the plaintext to military staff.

The information got from this was a great help to the Allied war effort. Ultra also included decrypts of other German, Italian and Japanese cyphers and codes, including the cypher of the German High Command.

Mistakes by German operators helped the cryptanalysis of Luftwaffe Enigmas, and the British capture of key tables and a machine from a German submarine helped in cracking Navy ones.

On 15th July 2011, Queen Elizabeth II visited Bletchley Park, where the machine is kept in the Museum, to pay tribute to those who worked there, since they cut short the war by breaking the cyphers of Nazi Germany.

Images for kids

Military Enigma machine, model "Enigma I", used during the late 1930s and during the war; displayed at Museo Nazionale Scienza e Tecnologia Leonardo da Vinci, Milan, Italy
A memorial to Marian Rejewski, the mathematician who first broke Enigma and educated the British and French about Polish methods of cryptanalysis
Enigma in use, 1943
Enigma rotor assembly. In the Wehrmacht Enigma, the three installed movable rotors are sandwiched between two fixed wheels: the entry wheel, on the right, and the reflector on the left.
Three Enigma rotors and the shaft, on which they are placed when in use.
Two Enigma rotors showing electrical contacts, stepping ratchet (on the left) and notch (on the right-hand rotor opposite D).
The Enigma stepping motion seen from the side away from the operator. All three ratchet pawls (green) push in unison as a key is depressed. For the first rotor (1), which to the operator is the right-hand rotor, the ratchet (red) is always engaged, and steps with each keypress. Here, the middle rotor (2) is engaged, because the notch in the first rotor is aligned with the pawl; it will step (turn over) with the first rotor. The third rotor (3) is not engaged, because the notch in the second rotor is not aligned to the pawl, so it will not engage with the rachet.
Internal mechanism of an Enigma machine showing the type B reflector and rotor stack.
The plugboard (Steckerbrett) was positioned at the front of the machine, below the keys. When in use during World War II, there were ten connections. In this photograph, just two pairs of letters have been swapped (A↔J and S↔O).
The Schreibmax was a printing unit which could be attached to the Enigma, removing the need for laboriously writing down the letters indicated on the light panel.
The Enigma Uhr attachment
German Kenngruppenheft (a U-boat codebook with grouped key codes).
Monthly key list number 649 for the German Air Force Enigma, including settings for the reconfigurable reflector (which only change once every eight days).
Figure 2. With the inner lid down, the Enigma was ready for use. The finger wheels of the rotors protruded through the lid, allowing the operator to set the rotors, and their current position, here RDKP, was visible to the operator through a set of windows.
Scherbius Enigma patent, U.S. Patent 1,657,411 , granted in 1928.
Typical glowlamps (with flat tops), as used for Enigma.
A rare 8-rotor printing Enigma model H (1929).
Heinz Guderian in the Battle of France, with an Enigma machine. Note one soldier is keying in text while another writes down the results.
Enigma in use on the Russian front
A three-rotor Enigma machine on display at Computer Museum of America and its two additional rotors.
Surviving three-rotor Enigma on display at Discovery Park of America in Union City, Tennessee, U.S.
A four-rotor Kriegsmarine (German Navy, 1. February 1942 to 1945) Enigma machine on display at the U.S. National Cryptologic Museum
A four-rotor Kriegsmarine Enigma machine on display at the Museum of the Second World War, Gdańsk, Poland
Enigma G, used by the Abwehr, had four rotors, no plugboard, and multiple notches on the rotors.
The German-made Enigma-K used by the Swiss Army had three rotors and a reflector, but no plugboard. It had locally re-wired rotors and an additional lamp panel.
An Enigma model T (Tirpitz), a modified commercial Enigma K manufactured for use by the Japanese.
An Enigma machine in the UK's Imperial War Museum
Enigma in use in Russia
Enigma in radio car of the 7th Panzer Div. staff, August 1941
A Japanese Enigma clone, codenamed GREEN by American cryptographers.
Tatjana van Vark's Enigma-inspired rotor machine.
Electronic implementation of an Enigma machine, sold at the Bletchley Park souvenir shop

Enigma (machine) facts for kids

Images for kids

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