A number of governments purchased Enigma machines in order to study them, and Edward Travis-the deputy head of Britain’s signals intelligence unit, the Government Code and Cypher School-bought one on behalf of the British government in the mid-1920s.
Models B, C, and D soon followed, and by 1927 Model D was selling widely for commercial use.
Scherbius had named his machine ‘Enigma’, and this ‘Model A’ was the first of a long line of models to emerge. This machine had a standard typewriter keyboard for input, and its design followed Scherbius’s original patent closely. In 1923, a company called Chiffrienmaschinen AG exhibited a heavy and bulky encryption machine at the International Postal Congress in Bern, Switzerland. In the early 1920s patent applications for a wheel-based cipher machine were filed by a Dutch inventor, Hugo Koch, as well as by a German engineer, Arthur Scherbius. The exact origins of the encryption machine that played such an important role in the Second World War are not entirely clear. It would take some of the best minds in Britain-and before that, in Poland-to crack German military Enigma. By the start of the Second World War a series of modifications to military Enigma had made the machine yet more secure, and Enigma was at the centre of a remarkably effective military communications system. The German military realized that its approach to cipher security required a fundamental overhaul, and from 1926 different branches of the military began to adopt the encryption machine known as Enigma. Shortly after the end of the First World War, the German Navy learned that its encrypted communications had been read throughout the hostilities by both Britain and Russia.