Enigma Machine Facts: The Cipher Machine Explained For Kids

The Enigma machine was an advanced cipher machine developed in Germany after World War I.

Ciphering is the technique of changing the letters of a message to make it appear as scrambled or random letters. When a letter is typed, it appears as another letter of the alphabet, but the choices of scrambling are not random.

Invention History Of The Enigma Machine

The invention of the Enigma machine was majorly a war strategy, for classified information exchange.

The credit of this invention goes to German engineer Arthur Scherbius, who came up with this secretive machine towards the end of World War I.

While several variants of Enigma models were made, the German military model, with a plug-board, was the most complex. This came at the time when Japanese and Italian models were also being used.

With minor modifications by the German Navy in 1926 and the German Army and Air Force soon after, Enigma was a popular name in military circles.

Before the start of the war, the German military was working out fast, mobile forces and tactics (blitzkrieg) that depend on radio communication to provide command and coordination.

However, radio signals could be easily intercepted, which led to the need for messages to be made secure by encryption. A compact and easily portable Enigma machine satisfied that requirement.

Over time, the German cryptographic techniques upgraded, and the Cipher Bureau developed techniques and designed mechanical devices to continue reading Enigma codes.

About 100,000 Enigma machines were made. The British and American governments managed to capture some of the Enigma machines, and later, sold them after World War II.

Purpose Of The Enigma Machine

This device was used by the German military command to encrypt strategy messages before and during World War II.

The Germans wrongly believed that the Allies would be unsuccessful in breaking their secret codes.

With an ordinary Morse code transmitter, encoded messages were sent, with one letter replaced by another.

An Enigma machine could be used in billions of ways to encode a message, and this made it almost impossible for the other nations to crack the German codes in times of war.

With a skilled team of expert code breakers, mathematicians, and experts in electronics, attempts were made to decrypt the Enigma machine codes. The team had a few members who excelled in chess, puzzle-solving, and primitive writing.

Team members were scattered in several huts located in Bletchley Park and were named the Government Code and Cipher School.

Alan Turing was a famous code breaker who developed multiple techniques to decrypt German codes. The British Government's Code and Cipher School had employed Turing part-time, before World War II.

In July 1942, Turing played a vital role in developing a complex code-breaking technique to be used against cipher messages produced by the Germans' new secret writer.

Features Of The Enigma Machine

For a small-sized machine that could cipher top-secret messages in the early days, the design was not as complicated as machines today.

The Enigma contains an electromechanical rotor machine to scramble the 26 letters of the alphabet. Most of the military Enigma machine models had three-rotor slots, though some had more.

One particular Enigma model had three enigma rotors in a rotor stack, sandwiched between two enigma wheels (the entry wheel and the reflector).

Several parts make up the Enigma machine including a keyboard, a lamp board, rotors, and internal electronic circuitry. An additional plugboard was in place for the ones used by the military.

For correct encryption and decryption of Enigma messages, both sender and receiver had to configure their Enigma in the same way including the rotor selection and order, ring positions, plug-board connections, and starting rotor positions had to be identical.

Apart from the starting positions, these settings were established in advance, distributed in key lists, and changed daily.

The security of the system depended on the machine settings that would get changed daily. This was done by following secret key lists that would be distributed earlier and on other settings that would be changed for each message.

The receiving station had to know and use the exact settings utilized by the transmitting station to be able to successfully decrypt a message.

Uses And Flaws Of The Enigma Machine

With the use of a cipher or encryption machine, there are bound to be flaws, either known or unknown.

Typically, one person enters the text on the Enigma's keyboard, while another person writes down which of the 26 lights above the keyboard illuminated at each keypress.

If plaintext is entered, the illuminated letters are the equivalent encoded ciphertext. Entering the ciphertext would transform it back into readable plaintext.

The rotor mechanism would change electrical connections between keys and lights with each keypress.

German military messages done on the Enigma machine were first cracked by the Polish Cipher Bureau, by December 1932.

This led to adding more complexity to the Enigma machines, from 1938, to make decryption more difficult.

Indeed, the code from the Enigma machine could not be easily deciphered, with efforts going on for months, with no success. It was a good four years from 1937-1941 that the German Navy's Enigma messages could not be broken.

On July 25, 1939, in Warsaw, the Polish codebreakers shared their cryptanalysis of the Enigma with their British and French intelligence agents, while promising each delegation a Polish-built Enigma.

The mistakes by some German operators worked in favor of cryptanalysis of the Enigma cipher. The British also captured key tables and a machine from a German submarine that helped crack Navy codes.

With technical developments, British codebreakers decoded several messages from Enigma and handed over the plaintext to the military staff. The information deciphered this way, called Ultra by the British, aided the Allied war efforts.

Additionally, Ultra involved decrypts of other German, Italian, and Japanese ciphers and codes including the cipher of the German High Command.

Alan Turing and his fellow codebreaker, Gordon Welchman, developed a powerful Bombe machine that cracked the Enigma code using a mechanized form of logical deductions.

This led to the German Air Force signals being read from the mid '40s. By the late '40s, the Bombe machine was decoding all Enigma code sent by machines.

The cracking of the Enigma codes was considered by some historians as the single most vital victory by the Allied powers during World War II. Having decoded the Germans' information enabled them to prevent several attacks.

Furthermore, to avoid the suspicion that they had cracked the German communications, the Allies did have to allow a few attacks on them, even though they had the knowledge to stop them.

A major flaw with the Enigma code was that a letter could never be encoded by itself. For example, an A would never be encoded with an A.

This huge flaw gave code breakers some information on how they could decrypt messages. By guessing a code or phrase that would probably appear in the message, they could use this information to start breaking the code.

Did You Know...

Alan Turing was an evolving English mathematician, computer scientist, codebreaker, and theoretical biologist.

Unfortunately, Turing died with the true extent of his groundbreaking innovations remaining largely unknown under the Official Secrets Act.

Bletchley Park functions as a museum now and includes several Enigma machines, along with other computing exhibits. You can also sight Enigma machines in the Science Museum and other museums in the US.

A three-rotor Enigma machine has been kept on display at the Computer Museum of America. Additionally, a surviving three-rotor Enigma is on display at Discovery Park of America in Union City, Tennessee, U.S.

On July 15, 2011, Queen Elizabeth II visited the place where the machine is kept in the museum at Bletchley Park. This was to honor the memory of those who worked there, as they were the ones who decoded ciphers of Nazi Germany and cut short the war.

'The Bletchley Circle,' which is a fictional television series of 2012, portrays a murderer being hunted by some code breakers. The 2014 film 'The Imitation Game' is based on the life of Alan Turing.