# Cryptography

#### Tag: WW2

Talking about Poland’s contribution to the Allies in World War II, apart from being on the battlefield, many guests mentioned that before the start of World War II, Poland laid the foundation for the final victory of the Allies. This is the Polish deciphering the German Enigma code. Pioneering work is done.

In 2014, with the release of the movie “Imitation Game”, the British mathematician Alan Turing, known as the “father of computer science”, began to receive public attention. The film mainly talked about Turing’s assistance to the Allies to decipher Enigma. The password, thus reversing the legendary experience of the Second World War. But because the film attributed Enigma’s deciphering to Turing, it also caused a lot of controversies.

As early as 1921, the Poles received a commercial Enigma cipher from the Germans, three outstanding graduates of the Poznan Institute of Mathematics, Marian Reyevsky, Gertz Rozki, and Henrik Zogarsky began to study its principles and tried to decipher.

Of course, the military Enigma cipher machine is more complicated than the commercial machine. The Polish wants to decipher it and must touch the actual machine. Fortunately, Hans Tillow Schmidt, who worked in the German Defense Password Office, handed the French intelligence agency a cryptographic machine manual and a button from September to October 1932. The instructions were set and the Frenchman handed it over to Poland.

At the end of 1932, the Poles had already derived the internal workings of the military Enigma cipher. Subsequently, the Polish company began to copy the Enigma cipher machine. At the end of 1938, the Poles also invented a cryptograph called Bombe, mechanized to simulate the encryption process, which is equivalent to the cooperation of six Enigma cipher machines. The “bombe” machine can find the key of the day within 2 hours, which can save hundreds of people’s manual work.

And for the German, the most significant mistake of them is that they even don’t know the machines and the ciphers were spread to the other countries, and the cipher the German used in WWll, were too similar to the cipher they used in the Wwl. This also provides many chances and helps to the Allies. And before the German-occupied the Polan, the Poles already give the Bombe machine to the British, this also helps Turing to further decipher the German cipher.

At the Brechley Manor, in addition to Knox, the deciphering community, there is also a mathematics wizard, Turing. He graduated from Cambridge University and relied on his research on cryptography after the war. He became one of the pioneers in the era of electronic computing.

First of all, they started with the development of a machine that can imitate or explain every “dummy mystery” of the German Defence Force, so that it can launch all the coding procedures that are frequently changed when the main command of the German army is issued day and night, and when the adult orders are issued. After a difficult attack, the British finally made the machine with the above functions and named it “bomb.”

At the end of 1939, the “bomb” deciphered the German code, and the British were ecstatic. Since then, the German secret plan and action plan has been continuously transmitted from the Brenchley Manor to Colonel Menzies, and then directly to Churchill’s desk. In fact, most of the German actions during the “World War II” failed to win the British, but the British have always concealed the source of intelligence, and have never caused doubts from opponents.

On July 2, 1940, Hitler released the first “Sea Lion” combat plan, which is also the British local landing operations plan. At the beginning of the campaign, Churchill and the Air Force staff learned most of the German Air Force – sometimes even all of them – through “super secrets”.

In response to the command of the German Air Force Commander Goring to seize the air superiority, the Royal Air Force has developed a plan to concentrate its superiority against the enemy. Since the number of aircraft of the British Air Force is not much in Germany, the fighter squadron and the main defensive forces can only be concentrated at the appropriate time, in the right place and at the appropriate height to deal with the enemy’s main attack power. Relying on early warning radars and deciphered German military intelligence, the Royal Air Force can always take advantage of the arrival of the Nazi Air Force to accurately intercept the interception, without the need for time and space patrols to guard against German raids – the British Air Force has greatly reduced the pilot’s physical consumption and gasoline Wait for strategic material consumption.

On August 13, 1940, over Sussex and Kent, 80 German “Donil 17” bombers, and a larger number of “Junker 88” dive bombers, flew to the British hinterland and coastline to carry out bombing missions. Due to the dense clouds in the sky, the German escort fighters could not take off as planned, and the bombers had to attack alone.

The British Air Force Command had already known the German action plan in advance. When the German plane was found on the radar, it immediately launched an operational plan that was already ready. In this confrontation, the German Air Force lost a total of 47 aircraft and more than 80 were injured. The British Air Force lost only 13 aircraft.

So actually in the WW1, the cipher of the German military should not be posted. It directly results in that the cipher of WW2 is deciphered.

The Germans had created one of the strongest ciphers of seen with the invention of the enigma. If they had kept standard practices and routine shifts in keys the cipher would have been impossible to decipher. The Germans originally planned on continued randomization of the day keys and plugboard settings. As the war went on, the randomness decreased and they began to use the same day keys and with more of a pattern. The Allied forces were able to build on the Polish achievements and spot these patterns, or cillies as they called them. Often times the same key would be used repeatedly just for the sake of easiness, disregarding the need for more security.

Another point of weakness in the German enigma was that methods in which they believed made their machine more secure actually made it easier to decrypt. Their idea that never making a swap between adjacent letters actually eliminated two possibilities on the plugboard. Also, never allowing a scrambler to be in the same spot two days in a row made sure that the same number was never repeated or that a scrambler was never in the same place twice. The codebook compilers reduced by half the number of possible scrambler arrangements as stated in The Code Book. This greatly reduced the combinations that codebreakers at Bletchley Park had to attempt.

The Germans had an impenetrable cipher that was flawed with human error. The Allieds Tipex and SIGABA ciphers both went unbroken throughout the entire war due to their increased complexity and diligence with sticking to proper protocol.

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