Why was bletchley park able to break the Enigma code

The Enigma Machine was a revolutionary coding device invented buy the Germans in 1919. It operated on a series of rotors and plugs and codes were able to be changed constantly to create over 150 Million Million code possibilities. No conventional code breaking methods would work against the Enigma as, if one code were cracked; another would replace it straight away. The Germans believed it impossible to crack. Bletchley Park was greatly helped to crack the Enigma by the Poles. The Poles needed to crack Enigma to defend themselves against the Germans but constant upgrades prevented them from getting very far.

By 1938, The Poles had managed to build their own replica Enigma from instructions obtained from a German cipher worker. They were now able to crack Enigma codes much easier. A mathematician called Marian Rejewski really made this possible as he largely built the replica Enigma machine and he also used mathematical data and reasoning to work out daily code settings. When the Poles were evacuated in 1939, Rejewski handed over all their work and the Enigma to the team at Bletchley Park. This greatly aided Bletchley Park in breaking the Enigma as they now had the machine to work on, making the whole operation more successful on the whole.

Ala Turing, a Cambridge graduate and mathematician, worked at Bletchley Park as an Enigma code breaker from the early stages of war. During his time there, he broke the ‘green’ cipher after realizing that information may have been mistranslated and so he went back to the original messages and looked over them again. He managed to spot clues or ‘cribs’ which helped him to crack it. He also developed the idea of the Bombe machine from what the Poles had devised which code cycle through code settings fast than any human and where therefore used all through Bletchley Park.

Technology was another major reason that the Enigma was cracked. The Bombe and Colossus were two such examples of how technology aided Bletchley Parks work. The Bombe had 30 rotors so it could cycle through 10 code settings at once. It could crack a code in hours rather than days and could work 24 hours a day 7 days a week. The Colossus was the first ever programmable computer system. Developed in 1943 by Tommy Flowers, it was an ‘upgrade’ to the Bombe. Colossus was paramount in breaking the ‘Dolphin’ cipher and the ‘Shark’ cipher (a four-rotor cipher).

It also broke ‘Fish’, Hitler’s personal code which was coded using the Lorenz code. John Herivel was a Cambridge Maths graduate and code breaker at Bletchley Park. He broke the German Army’s ‘Red’ cipher using his imagination and logic and working out that German code operators were not changing their code setting regularly. He helped Bletchley Park break the Enigma because he spotted the human error in the Germans’ work and was able to exploit it to their advantage. German Mistakes was another reason for the Enigma being cracked.

The Germans believed the Enigma impossible to crack and so they were not a careful as they should have been. One of the biggest mistakes was leaving their weather ships unguarded, all of which had Enigma machines and codebooks on board. The British found out about the ships and captured them immediately giving them access to Enigma machines and about 6 month’s worth of code settings. Another mistake was that the Germans would send weather reports daily which could be deciphered using the method of ‘cribs’.

If a code breaker could find the word ‘Weather’ or in German ‘Wetter’, the may be able to solve the whole day’s code. All of the above reasons are linked. For example, the Poles and Rejewski are linked with the work if Alan Turing because without their help and ideas, Turing might never have developed the Bombe from Rejewski’s original idea. Another link is between Turing and the development of technology at Bletchley Park. Turing ‘s Bombe opened up possibilities for technology no one had ever thought of, allowing machines like Colossus to be built.

John Herivel and German mistakes are also linked because if the Germans had made sure their code settings were changed regularly and they had not become lazy, Herivel would never have been able to guess they were doing so. Bletchley Park was able to break the Enigma because of all these reasons, but I believe the most important reason is the work of the Poles and Rejewski. Without them, Bletchley Park would never have had a replica Enigma or even have been able to think of building a machine such as the Bombe.