Cracking Enigma Code
Introduction
It is estimated that Cracking Enigma code shortened World War II for approximately 2 – 3 years. It certainly changed the history. I don’t want to think what would happen if German cipher wasn’t cracked. Some say that, with some degree of probability, One American plane could be sent to fly over Central Europe, instead of Hiroshima… (?).
For those of you who haven’t seen The Imitation Game, Milton Keynes was just a small village with population of only 50. This was perfect for British Government so they bought #Bletchley Park estate to house the most secret codebreaking and intelligence efforts of the Government Code and Cypher School – GC&CS (currently known as Government Communications Headquarters – GCHQ).
The standard three-rotor Enigma was capable of being set to approximately 159,000,000,000,000,000,000 possible combinations.
How Enigma works
The basic purpose of every Enigma machine is simple to take a message and turn it into a secret (scrambled set of characters). Enigma machine do not transmit messages. It was to encrypt the messages only. These (encrypted) messages were sent in Morse code by a radio using radio equipment. Messages were then decrypted when received.
The Enigma used rotors to scramble messages into unintelligible cipher text. The German military adapted an early commercial version (3 rotors), marketed for the banking industry and believed to be impennetrable.
By 1938 the number of rotors to choose from each day was increased to five. The German Navy also used the same five rotors and later, an additional three, unique to them.
Why Cracking Enigma was so difficult to achieve then?
Rotors were wired differently and there was a choice of up to 5 rotors for Army and Air-Force machines and up to 8 for Naval machines.
There could be 3 or 4 rotors in use at any one time and the more rotors, the more possible permutations (to scramble text).
The rotor and plug-board settings changed every day at midnight.
There was no “universal” Enigma setting for the day – each branch of military, the intelligence services and the civil services used different machines and also different settings for sections within their operations.
It is estimated that there was about 200,000 Enigma machines and the same number of operators. It is amazing but cryptologists worked at Bletchley Park could recognize some of them by the way they were sending Morse Code “keystrokes”… To me that sounds almost impossible but this “skill” gave them ability to geographically pin point location of some of the Enigma operators and make strategic decisions based on that fact.
The Bombe machine was developed by Alan Turing and Gordon Welchman to speed up the breaking of Enigma.
The Codebreakers created a menu for the wiring at the back of the Bombe based on a hypothesis, known as “crib“, a part of the original message. Cribs were often derived from regular appearances in deciphered messages of stock phrases, such as “message number” or “nothing significant to report”.
One of Enigma’s fatal flaws was that no letter could ever be enciphered as itself. When sending Enigma message, the Germans spelt out numbers as words, not numerals. The word EINS, meaning number 1, appeared in nearly all messages. But there were still over 17,000 ways in which EINS could be encrypted. The codebreakers worked out all these combinations and stored them in alphabetical order in the “EINS catalogue“.
Polish Mathematicians
Marian Rejewski (16 August 1905 – 13 February 1980) – was a Polish mathematician and cryptologist who reconstructed the Nazi German military Enigma cipher machine sight-unseen in 1932. The cryptologic achievements of Rejewski and colleagues Jerzy Różycki and Henryk Zygalski enabled the British to begin reading German Enigma-encrypted messages at the start of World War II, seven years after Rejewski’s original reconstruction of the machine.
Jerzy Różycki (24 July 1909 – 9 January 1942) – was a Polish mathematician and cryptologist who worked at breaking German Enigma-machine ciphers before and during World War II.
Henryk Zygalski (15 July 1908 – 30 August 1978) – was a Polish mathematician and cryptologist who worked at breaking German Enigma ciphers before and during World War II.
In July 1939, aware that Poland would soon be invaded, the Poles shared the work of their mathematicians who had worked on Enigma with the British the the French. By this time the Germans were changing most of the Enigma settings daily and the British wartime breaks into the daily-changing Enigma code took place at Bletchley Park in January 1940.
During the war, polish mathematicians were not involved in any of the Bletchley’s Park top secret operations at all. They were transported to London to support polish government. Please bare in mind they still had friends and families in Poland, therefore, for obvious reasons they were not invited to join the party.
If you are interested in the subject, there was a really beautiful and informative TV series called Time of Honor, released by polish producers. Follows a group of young officers parachuted back into Poland to help the resistance movement during World War II. War drama about “Silent Unseen” (pol. Cichociemni). SIlent Unseen were predecessors of Polish elite special forces called GROM, modelled after US Delta Force and Navy Seals. Time of Honor is a must see TV series if you are interested in a subject of WW II!
Around December 1932, Marian Rejewski of the Polish Cipher Bureau used the theory of permutations and flaws in the German military message procedures to break the message keys of the plugboard Enigma machine. Rejewski did that without knowing the machine wiring, so the result did not allow the Poles to read any messages. However, the French had a spy with access to German cipher materials that included the daily keys used in September and October 1932. Those keys included the plugboard settings. The French gave the material to the Poles, and Rejewski used some of that material and the message traffic in September and October to solve for the unknown rotor wiring. Consequently, the Poles were able to build their own Enigma machines, which were called Enigma doubles. Rejewski was aided by cryptanalysts Jerzy Różycki and Henryk Zygalski, both of whom had been recruited with Rejewski from Poznań University. The Polish Cipher Bureau developed techniques to defeat the plugboard and find all components of the daily key, which enabled the Cipher Bureau to read the German’s Enigma messages. Over time, the German cryptographic procedures improved, and the Cipher Bureau developed techniques and designed mechanical devices to continue breaking the Enigma traffic. As part of that effort, the Poles exploited quirks of the rotors, compiled catalogs, built a cyclometer to help make a catalog with 100,000 entries, made Zygalski sheets and built the electro-mechanical cryptologic bomb to search for rotor settings. In 1938, the Germans added complexity to the Enigma machines that finally became too expensive for the Poles to counter. The Poles had six bomby, but when the Germans added two more rotors, ten times as many bomby were needed, but the Poles did not have the resources.
source: Wikipedia
People of Bletchley Park
It is estimated that about 10,000 people worked in Bletchley Park during the war (remember, Milton Keynes was only a small village with population of 50 people) and approximately another 10,000 overseas, intercepting German messages (at so called “Y stations“) and spying.
First question that came to my mind was: How British Intelligence (GC&CS) actually managed to keep the whole operation in secret?
Well, apparently they employed very loyal people indeed. They didn’t talk about what they do. Simple as that (is it?). Those that are still alive, still don’t talk (as far as I remember correctly confidentiality documents they signed at the time expired in 1974).
Women made up the majority of the personnel at Bletchley Park, and not only in supporting roles: they made a significant contribution to the codebreaking process.
Alan Turing (1912 – 1954) sculpture at Bletchley Park. Mathematician – codebreaker.
Visiting Bletchley Park
If you got that far and didn’t fall asleep means that you are seriously interested in a subject.
On the official website of Bletchley Park Trust you can find more information about visiting times, address and even download an app.
Adult ticket costs £17,50 and is valid for a year (Feb 2017).
