Enigma was one of the first electromechanical machines used for the encryption and decryption of messages. Such devices offered not only more efficient encryption, but also resistance to the statistical and linguistic attacks that were then used. The first Enigmas were built in the 1920s and were aimed at the consumer market. In spite of Enigma’s lack of commercial success, its capabilities were appreciated by the German military. For military usage, the machine was additionally modified to increase the number of possible settings to approximately 1016. The properties of the military Enigma gave its creators confidence that the machine would provide an unbreakable radio communication system. A secure method of radio communication was a key element of the very successful German strategy of –“”Blitzkrieg, or lightning war.

Polish cryptologists

The appearance of a new German cipher proved quite a challenge for the intelligence agencies of other European countries. The Polish Cipher Bureau came up with the interesting idea of hiring mathematicians to break ciphers (formerly, linguists, chess masters and puzzle-lovers had been used). To that end, in the late 1920s, a cryptology course was organized at the University of Poznań. Professor Zdzisław Krygowski was asked to pick the best students. Among the participants were Marian Rejewski, Jerzy Różycki and Henryk Zygalski, who were all later employed at the Poznań branch of the Cipher Bureau. In 1932, Marian Rejewski began work on the Enigma cipher. Using permutation theory, he developed a theoretical method that reduced the complications introduced in the military Enigma. As a consequence, the problem of finding the daily setting of the machine was simplified by a factor of approximately 100,000,000,000. To utilize this method, the design of the military machine had to be learned, and this was accomplished by a clever application of mathematics and certain information obtained by French intelligence. As a result, several replicas of Enigma were made, as well as several methods of breaking it. In time, machines were built to make the decryption process significantly easier. In 1938 the Germans introduced modifications to Enigma, which necessitated large increases in the number of cryptanalytic machines. This exceeded the financial capacity of the Polish intelligence service; in addition, there were more and more indications that the outbreak of war was imminent. In light of this, the Poles decided to transfer the replicas of the German cipher machine, along with the decryption methods, to the French and British. This information proved invaluable, especially to the British, who were quickly able to build and significantly improve on the Polish machines, and thus prepare to for the Battle of Britain. According to historians, the breaking of the German cipher was of huge importance for the course of World War II. It is commonly thought that this Polish achievement contributed to a significant shortening of the war, which probably prevented the use of nuclear weapons in Europe. Cryptanalytic machines also played a very important role in the birth of computer science.