About hundred years later the invention of the strongest, most challenging and most sophisticated device so far was strengthening the position of the cryptographers. The Enigma, developed by the German Arthur Scherbius, offered unequalled opportunities and showed the importance of cryptography to military and civil intelligence. Scherbius was born 1878 in Frankfurt am Main, was an electrical engineer and already held a number of patents. His first design of the Enigma was called Model A and was a monster about the size and shape of a cash register (50 kg). Then followed Model B and Model C, that was a portable device in which the letters were indicated by lamps. The Enigma machine looked like a typewriter in a wooden box. Describing the internal design of the Enigma would go far beyond the scope of this text and is already covered by many articles and Enigma-Emulators in the internet (see links below).
Therefore we will take a closer look on Arthur Scherbius. He called his machine Enigma, which is the Greek word for "riddle". He acquired the patent 1918, but he was not the only one exploring the principle of rotor machines. At the same time also Hugo Alexander Koch (Netherlands), Arvid Damm (Sweden) and Edward Hebern (US) sketched out their own designs of such a device, but they all could not make a big deal. Scherbius was first confronted with similar problems, because no one showed interest or even noticed his invention. However Scherbius was convinced that his Enigma would make a market. After all the German Army was interested in a new cryptographic device because of several disappointments in the past. The serial production of the Enigma started in 1925 and the first machines came into use in 1926. Scherbius' Enigma provided the German Army with the strongest cryptographic cipher of the world and the military conversation of the Germans was optimally protected during World War II. Scherbius however didn't experienced the rise and fall of his machine. He died in 1929 in consequence of an accident with a horse carriage, that went out of control and crashed against a wall.
Breaking the Enigma
Since 1926 English cryptanalysts in Room 40 were eavesdropping German radio messages without being able to extract their meaning. The Americans and the French were also powerless in the face of the cryptographic strength of the Enigma. Whereas the Allies early gave up in decrypting these messages and relied on the lost power of Germany after World War I, Poland felt the threat of being attacked and established a new cipher office called Biuro Szyfrów. It started making attempts to analyse and break the Enigma and was assisted by documents passed to them by the French stolen by a German spy named Hans-Thilo Schmidt. With his help and years of intensive and ingenious work three brilliant cryptanalysts, Marian Rejewski, Henryk Zygalski and Jerzy Rozicki, succeeded in breaking the Enigma in 1933. They developed a machine called the Bomba, that made the process of codebreaking even faster. In July 1939, the Poles, fearful of Germany, gave the secrets of their research to the British and the French. They had to cope with an increased sophistication of the Enigma which made further attempts necessary. At Bletchley Park the British bombe was designed by Alan Turing and Gordon Welchman, which was absolutely different to the Polish bomba and finally helped to decipher the German messages. Although the British bombe actually owes little to the Polish bomba, the immense contribution of the Poles of supplying the internal wiring of the Enigma's rotors and the demonstration that the Enigma could be broken by a machine has to be much valuated.