Until the release of the Oscar-nominated film The Imitation Game in 2014, the name ‘Alan Turing’ was not very widely known. But Turing’s work during the Second World War was crucial. Who was Turing and what did he do that was so important?
Tool to decrypt/encrypt with Enigma automatically. Enigma is a german ciphering/deciphering machine. Based on an electromechanic system using rotors, it allowed to cipher. Inspect the encryption and decryption of the Enigma cipher machine step by step. Current configuration is impossible with a physical (standard) enigma:! The configuration of the Engima cipher machine has three parts: The wheels with overflows and offsets (via the whell rings).
Mathematician
Alan Turing was a brilliant mathematician. Born in London in 1912, he studied at both Cambridge and Princeton universities. He was already working part-time for the British Government’s Code and Cypher School before the Second World War broke out. In 1939, Turing took up a full-time role at Bletchley Park in Buckinghamshire – where top secret work was carried out to decipher the military codes used by Germany and its allies.
Enigma and the Bombe
The Enigma Cipher The Enigma Cipher. Perhaps the most famous cipher of recent years is that used with the Enigma Machine. It was developed by Arthur Scherbius in 1918, but gained widespread notoriety when it was used by German Intelligence during World War. An Enigma machine is a famous encryption machine used by the Germans during WWII to transmit coded messages. An Enigma machine allows for billions and billions of ways to encode a message, making it incredibly difficult for other nations to crack German codes during the war — for a time the code seemed unbreakable. Alan Turing and other researchers exploited a few weaknesses in the.
The main focus of Turing’s work at Bletchley was in cracking the ‘Enigma’ code. The Enigma was a type of enciphering machine used by the German armed forces to send messages securely. Although Polish mathematicians had worked out how to read Enigma messages and had shared this information with the British, the Germans increased its security at the outbreak of war by changing the cipher system daily. This made the task of understanding the code even more difficult.
Turing played a key role in this, inventing – along with fellow code-breaker Gordon Welchman – a machine known as the Bombe. This device helped to significantly reduce the work of the code-breakers. From mid-1940, German Air Force signals were being read at Bletchley and the intelligence gained from them was helping the war effort.
Hut 8, Bletchley Park
Turing also worked to decrypt the more complex German naval communications that had defeated many others at Bletchley. German U-boats were inflicting heavy losses on Allied shipping and the need to understand their signals was crucial. With the help of captured Enigma material, and Turing’s work in developing a technique he called 'Banburismus', the naval Enigma messages were able to be read from 1941.
He headed the ‘Hut 8’ team at Bletchley, which carried out cryptanalysis of all German naval signals. This meant that – apart from during a period in 1942 when the code became unreadable – Allied convoys could be directed away from the U-boat 'wolf-packs'. Turing’s role was pivotal in helping the Allies during the Battle of the Atlantic.
Turingery and Delilah
In July 1942, Turing developed a complex code-breaking technique he named ‘Turingery’. This method fed into work by others at Bletchley in understanding the ‘Lorenz’ cipher machine. Lorenz enciphered German strategic messages of high importance: the ability of Bletchley to read these contributed greatly to the Allied war effort.
Turing travelled to the United States in December 1942, to advise US military intelligence in the use of Bombe machines and to share his knowledge of Enigma. Whilst there, he also saw the latest American progress on a top secret speech enciphering system. Turing returned to Bletchley in March 1943, where he continued his work in cryptanalysis. Later in the war, he developed a speech scrambling device which he named ‘Delilah’. In 1945, Turing was awarded an OBE for his wartime work.
The Universal Turing Machine
In 1936, Turing had invented a hypothetical computing device that came to be known as the ‘universal Turing machine’. After the Second World War ended, he continued his research in this area, building on his earlier work and incorporating all he'd learnt during the war. Whilst working for the National Physical Laboratory (NPL), Turing published a design for the ACE (Automatic Computing Engine), which was arguably the forerunner to the modern computer. The ACE project was not taken forward, however, and he later left the NPL.
Legacy
In 1952, Alan Turing was arrested for homosexuality – which was then illegal in Britain. He was found guilty of ‘gross indecency’ (this conviction was overturned in 2013) but avoided a prison sentence by accepting chemical castration. In 1954, he was found dead from cyanide poisoning. An inquest ruled that it was suicide.
The legacy of Alan Turing’s life and work did not fully come to light until long after his death. His impact on computer science has been widely acknowledged: the annual ‘Turing Award’ has been the highest accolade in that industry since 1966. But the work of Bletchley Park – and Turing’s role there in cracking the Enigma code – was kept secret until the 1970s, and the full story was not known until the 1990s. It has been estimated that the efforts of Turing and his fellow code-breakers shortened the war by several years. What is certain is that they saved countless lives and helped to determine the course and outcome of the conflict.
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The Enigma Cipher
The Enigma Cipher
Perhaps the most famous cipher of recent years is that used with the Enigma Machine. It was developed by Arthur Scherbius in 1918, but gained widespread notoriety when it was used by German Intelligence during World War II, and subsequently cracked by the team at Bletchley Park.
What is the Enigma Machine?
The Enigma machine is essentially a complicated substitution cipher machine. It consists of a plug board, a light board, a set of rotors and a reflector.
The machine came with a number of rotors, each of which rotor contained a random substitution alphabet. The user would select between 3 and 5 rotors to use at any one time, depending on the size of the machine. The plug board was another variable for the machine. Certain letters would be connected reciprocally to each other.
The Encryption Process
Each month, the German code sender (??) would receive a code book outlining the key to be used for each day. A day key might look like this:
Plug board: | (A,I) (J,F) (E,M) (Z,X) (W,O) (S,B) |
Rotors: | 2,3,1 |
Rotor key setting: | KWO |
The machine itself looked like an old fashioned typewriter. When the user pressed the letter to be encoded, it would first pass through the plug board, then through the 3 rotors, the reflector, and back through the rotors in reverse. The encrypted letter would then be lit up on the display. Firstly the operator would set up the plug board as indicated, then would arrange the rotors and finally set the rotors to the day key.
The plug board randomly paired 12 letters to each other. So, if H was mapped to P, P would be mapped to H. The remaining rotors map each letter to another. The encrypted letter reaches the reflector, which unlike the rotors does not rotate, so the mappings remain the same. It then passes back through the reversed rotors.
All in all, the letter passes through a minimum of 7 re-mappings (if the letter is not connected to another on the plug board), and a maximum of 9 re-mappings (if the letter is connected to another on the plug board). Before the next letter would be encoded, the right hand rotor would rotate. The middle rotor would rotate once the right hand rotor had done a complete revolution, and likewise the left hand rotor would rotate once the middle rotor hand undertaken a complete revolution.
The Day Key
They decided to use different keys for each message by setting their machine to the key of the day, e.g. COU, and sending the new key, e.g. NTO encrypted twice, resulting in ZJMELF. The receiver could then decrypt the message using the key of the day and would know to set his or her machine to the new key NTO for the new message.
How Does it Work?
As they were sending hundreds of messages every day, the German’s realised that using a single key every day could decrease the security of the system as it would give the enemy more information to work with in a single key.
The machine consists of a series of 3 rotors, each of which substitutes the original plaintext letter for another. Let us call them rotor 1, rotor 2, and rotor 3. Each rotor is set to encode a specific cipher.
Let’s illustrate this by encoding a single letter, the letter ‘H’.
Rotor 1 will encode the plaintext as follows:
Rotor 1 will encode the plaintext as follows:
INPUT | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Rotor I | E | K | M | F | L | G | D | Q | V | Z | N | T | O | W | Y | H | X | U | S | P | A | I | B | R | C | J |
H → Q
Rotor 2 then takes our new letter Q and encodes this:
INPUT | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Rotor II | A | J | D | K | S | I | R | U | X | B | L | H | W | T | M | C | Q | G | Z | N | P | Y | F | V | O | E |
Q → Q
The Q is then passed through Rotor 3:
INPUT | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Rotor III | B | D | F | H | J | L | C | P | R | T | X | V | Z | N | Y | E | I | W | G | A | K | M | U | S | Q | O |
Q → I Flexiglass 1 0 intelk download free.
Enigma Machine Decoder
At this stage, the encrypted letter reaches the reflector. This was also set to a predetermined encryption. This is the Reflector C:
INPUT | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Reflector | F | V | P | J | I | A | O | Y | E | D | R | Z | X | W | G | C | T | K | U | Q | S | B | N | M | H | L |
Enigma Cipher App
I → E
As you can see, there are only 13 permutations in the reflector, because the letters are arragned in pairs. So,
Piggystocks 1 2 – monitor your portfolio stock. Now the encrypted letter passes back through the rotors, this time set in the inverse position. So, rotor 3 now looks like this
Piggystocks 1 2 – monitor your portfolio stock. Now the encrypted letter passes back through the rotors, this time set in the inverse position. So, rotor 3 now looks like this
INPUT | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Rotor III | T | A | G | B | P | C | S | D | Q | E | U | F | V | N | Z | H | Y | I | X | J | W | L | R | K | O | M |
E → P
Rotor 2 has also been reversed and appears like this:
INPUT | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Rotor II | A | J | P | C | Z | W | R | L | F | B | D | K | O | T | Y | U | Q | G | E | N | H | X | M | I | V | S |
P → U
Enigma Cipher Code
Finally our encoded letter passes through the inverse rotor 3:
INPUT | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Rotor III | T | A | G | B | P | C | S | D | Q | E | U | F | V | N | Z | H | Y | I | X | J | W | L | R | K | O | M |
U → W
The Maths Behind the Enigma
Even though the Enigma machine had a huge number of possibilities for each letter, it still weaknesses that were exploited by the team at Bletchley Park and eventually were its downfall.
Problems with the Enigma
It also guarantees that it is impossible for a letter to be encoded as itself. This was vital to the team at Bletchley Park who helped decode the Enigma.
![Enigma Cipher Enigma Cipher](https://cdni0.trtworld.com/w960/h540/q75/8749-trtworld-399671-438795.jpg)