From Commercial to Military Use
Until the Second World War, the most advanced forms of encryption involved simple paper and pencil techniques. But security blunders on both sides during the First World War highlighted a need for a higher level of secrecy, with more advanced methods of enciphering messages. Both the Allies and the Axis countries were looking for a new way to encrypt messages - a way that would result in complete security.
In 1915 two Dutch Naval officers had invented a machine to encrypt messages. This encryption tool became one of the most notorious of all time: the Enigma cipher machine. Arthur Scherbius, a German businessman, patented the Enigma in 1918. German banks and railways were among its first customers, but the German military was quick to see its potential. In 1926 the commercial Enigma was purchased by the German Navy and adapted for military use. By 1928, the German Abwehr (Secret Service), Wehrmacht and Luftwaffe bought their own version, and revised this machine; adding the plugboard and a different stepping mechanism. This version became known as the Wehrmacht Enigma and was introduced on a large scale to the German Army and public authorities. Back in those days, an individual unit would cost roughly as much as $60,000 in today’s prices.
The Enigma machine's place in history was secured in 1924 when the German armed forces began using a specially adapted military version to encrypt their communications. They continued to rely on the machine throughout the Second World War, believing it to be absolutely unbreakable.
Each day German operators in the field received a new set of instructions from base on how to set up the Enigma. They had to make three adjustments so that both the sender's and receiver's machines would match:
1. Which rotors to put into the machine and in what order - the rotors contained one of the central secrets of the Enigma machine, which was the cross wiring inside the wheels. The whole of this maze of wiring inside changed every time a letter was entered and that's what gave the Enigma machine its vast complexity.
2. To change the wiring of each rotor, operators had to adjust the ring of letters around the rim - 26 combinations on each wheel.
3. Using his secret instructions for the day, the operator could wire up each typewriter key to a totally different letter.
This was what the Germans thought was the killer cryptographically. This plugboard enabled you to transpose letters completely, a pair of letters. Now because there are 26 sockets on the front of the Enigma machine, you can plug these pairs of letters together in an absolutely astronomical number of combinations.
Once the machine was set up, the message was encoded letter by letter. These letters were then sent by Morse code to the receiver at the other end. The Germans were never shaken in their belief in Enigma's invincibility. At first, all the codebreakers had were meaningless groups of coded letters and endless patience. And in the first months of the war the new recruits were getting nowhere.
The total number of ways in which the Enigma machine can be configured for any particular message is 150 million million million. So it was an enormous complexity which was why the Germans thought it was completely safe.
Enigma Cipher Machine Homepage: Jamie Brownell
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