The enigma machine had one of the most complicated encrypting systemsof that time. This encrypting system used a number of rotors to scramblethe electrical signals (representing letters) that were passed through themachine. It has places for three different rotors.
Early on there were fiveto choose from, but later in the war, the Germans added a sixth one makingit even harder to crack. Each of these rotors had 26 electrical contacts oneach side. Each of the electrical contacts on the first side of the rotorwas connected to a single contact on the other side, such that this secondcontact stood for a different letter (eg “W” to “A”). Typing of each letterin the signal to be encrypted or decrypted caused an electrical current topass through all the rotors. While signals were being typed, the currentalso turned the rotors at different speeds, one fast one slow and one inthe middle. This was all part of the scrambling process.
The operator would put the letter ‘A” into the machine for example, onthe very same rotor it would be changed to “H” the connected contact onrotor 1. Then going to the second rotor it would be changed to “F” which atthe time would be alined to “H”. The “F” would then be changed to theconnected contact on rotor 2 and then be passed on to the aliened letter onrotor 3 eg “P”. The “P” would be changed to the connected contact so it maycome out as “G”. Now comes the ultimate bit – the German Enigma machine had a reflectoron it which sent the encrypted letter back through the machine furtherencrypting it. The reflector worked with 13 pairs of letters.
“G” would bechanged to its paired number for example “X”, the whole thing would workagain, and the letter would be changed all over again. The moving Rotorsalso meant that if a word contained two of the same letter’s for Attack thetwo T’s could turn out to be A and V making the message even harder tocrack. The Germans changed the Rotor numbers and starting positionseveryday. The machine had two sets key boards one to type the message and onewhich had light’s under it. The light’s showed the letter which theoriginal letter had been encrypted to. The operator had to write these downso he would know what to send with Morse code.
THE STEPS INVOLVED IN CRACKING THE CODE AND A GENERAL OVERVIEW OF HOW ALLBEGAN: After its defeat in the First World War, the German defence forcewanted to improve the security of communication in the German armed forces. The answer came when Dr Arthur Scherbius developed an enigma machine. Heset up a company in 1923 in Berlin and called it the ChiffriermaschinenAktiengesellschaft (cipher machines corporation) in the hope large;companies would be interested in them for secure communication. The Germansaw the enigma machine and three years later, the German navy was makingtheir own enigma machines and the army and air force soon followed. Themachine was improved over the years. The allied code breakers got there first look at what they were upagainst when a German spy allowed his French spy masters to photographstolen enigma manuals.
The Polish cipher bureau made the first big stepthey managed to reconstruct an enigma machine. They were reading Germanmessages between 1933 and 1938. In 1939, the Polish cipher bureau shared its work with the British codebreakers at Bletchley Park in Buckinghamshire. Bletchley Park was one ofthe best-kept secrets of the war and it was not revealed what part it hadplayed until 1974 nearly 30 years after the war had finished. Manymathematicians and problem solvers were recruited and huge computers called”bombs” were built to work out the many different enigma settings.
Anyinformation gained on the enigma was known as Ultra and was top secret. Only very, few knew about what was being done at Betchley Park. It was hopethat the Germans would not know that any of their ciphers had been broken. It was a while before the work had any impact on the war effort oftenbetter information was gathered by integrating prisoners, aerialreconnaissance and captured documents.
In 1941, a breakthrough was made. Evidence from reading parts of messages told them of the German in build upprior to the invasion of Greece. However, the British did not have theforces to exploit this. Later that year Bletchly Park cracked an Italianenigma message, this helped Admiral Cunningham’s Mediterranean fleet defeatthe Italians at the battle of Matapan.
Later the ciphers used by RommelsAfrika Korps, were broken now they would know his next move and everynearly every course his supply ships would take. This was a huge advantageand turned the battle for Africa in favour of the British. Bletchley Park now turned its attention onto breaking the U-boat codes. The U-boats were stoping many supplies from reaching England and it washoped that if the code could be broken that supply ships could be kept awayfrom the danger areas. To do this they had to capture an enigma machine andits codebooks.
In April 1941, the German Trawler “Krebs” was captured. Along with two enigma machines and a list of the rotor settings rotornumbers for the next month. For one month the British could read the enigmamessages but with some delay. In May, the Mnchen was captured along withthe setting’s for the month of June.
Then the settings for the month ofJuly were captured now the code breakers at Bletchley Park were reading themessages almost without any delay. All these events lead the Germans to try to tighten the security of thecode but all it did was to increase the funding of Bletchley Park. TheGermans then installed a forth Rotor multiplying the number of settingsanother 26 times. The resulting game was known to the Germans as “Triton”and to the British as “Shark” for over a year the British could notpenetrate any further into the enigma. Better computers from the USA helpedthe British once again in being able to read the German navel messagesregularly. The cracking of the enigma played a large part in the outcome of thewar it helped stop Rommel in Africa, the U-boats and many other operations.
The cracking of the Enigma took them the best part of 7 years and eventhen, they could not read every message that was sent. The figures showsthat of over 5 million messages intercepted during the war only about 50,00were ever read that’s less then 1% of messages intercepted. pic An enigma machineTHE COMPUTER PROGRAM: This is a Enigma simulator I got off the internet it works exactly thesame way as the real version. It shows the rotors moving and the lightsthat come up under the encrypted letter.
First you choose the Rotor numbers I have chosen “6”, “3”, “5” and “4” mystarting positions will be “K”, “S”, “L” and “U”. I then type my messagein. THE ENIGMA CODEIt comes back scrambled asAPNOY UTAPS FVXI then set the rotors back to their original position, and type theencrypted message inAPNOY UTAPS FVXAnd I get the message backTHEEN IGMAC ODEWhich comes toTHE ENIGMA CODE. |Geheim! Secret indeed! This is an example of the setting sheets used.
It||has the day Rotor number and starting position on it. ||pic |picBletchley Park
