Enigma was widely used in World War II. It was the most popular encoder in Germany, Italy, Japan and even neutral Switzerland. The "fathers" of the legendary encryption machine, whose name means "mystery" in Greek, were the Dutchman Hugo Koch (inventor of the encryption disk) and the German engineer Arthur Scherbius, who patented the encryption machine back in 1918.
Arthur Scherbius is the author of Enigma. Source: lifeofpeople.info
Initially, there was no question of any military career of "Enigma" - it was a typical commercial product. There was even a massive advertising campaign initiated by Scherbius to promote his own product. So, in 1923, the encryption apparatus became an exhibit at the congress of the International Postal Union, but did not gain success. The reason was the high price of the Enigma and the impressive size of the Scherbius car. And yet, several copies were sold to the armies of various countries and communications companies. The British first encountered the Enigma device in June 1924, when the manufacturer offered the British to buy a batch of devices at a considerable price of $ 200 apiece for that time. The British government responded by offering to register the encryption novelty with the patent office, which automatically led to the provision of complete documentation for the technique. The Germans took this step and British cryptographers got at their disposal all the technical nuances of the Enigma long before the Second World War.
Patent for "Enigma". Source: lifeofpeople.info
However, it is worth noting that the Enigma was in an early commercial version, which the Germans did not use in their army. The ascent of the German cipher machines to Olympus began with the coming to power of Adolf Hitler in 1933, when the rearmament of the army began. The total number of Enigma vehicles produced until the end of World War II, according to various sources, varies from 100 thousand to 200 thousand. They were used everywhere - in the Wehrmacht, in the Kriegsmarine, in the Abwehr, in the Luftwaffe and in the fascist security services.
"Enigma" later version. Source: w-dog.ru
What is the encryption device based on? In the very first generation, these were three drums (discs or wheels) rotating in one plane, on each side of which there were 26 electrical contacts - exactly the number of letters in the Latin alphabet. The contacts on both sides were connected inside the disk by 26 wires, which formed the replacement of characters when typing. During the assembly process, three discs were folded together, touching each other with contacts, which ensured the passage of electrical impulses through the entire set of drums to the recording device. The Latin alphabet itself was engraved on the side of each drum. The beginning of work with the "Enigma" -transmitter was marked by a set of a code word from letters on the drums. It is important that the receiving device is also configured with the same codeword.
Field encryption machine "Enigma". Source: musee-armee.fr
Then the operator responsible for entering the text for encryption types on his keyboard, and each press causes the left disk to be rotated one step. The Enigma was an electromechanical machine, so all commands to the mechanical part were given using electrical signals. After the left disk was turned one revolution, the central drum came into play, and so on. This rotation of the discs created for each character of the text its own unique contour for the passage of an electrical impulse. Then the signal passed through the reflector, which consisted of 13 conductors connecting pairs of contacts on the back side of the third disc. The reflector turned the electrical signal back into the drums, but in a completely different way. And only here the light came on near the letter of the already ciphered text. Such "adventures" of the electrical signal provided a unique security for the communication channel for their time.
A military version of Enigma with four drums. Source: e-board.livejournal.com
Given the further improvements the Germans made to Enigma, British cryptanalysts would never have been able to hack such a sophisticated apparatus on their own. At first, three people worked with "Enigma": one was reading the text, the second was typing on the keyboard, and the third was writing down the cipher by the flashes of light bulbs. Over time, the size of the encryption apparatus decreased to the size of a typewriter, which made it possible to send messages from literally every trench. Also, during the modernization, the Germans added a printing device for typing cipher text. What else have the Third Reich cryptographic engineers added to Enigma? In 1930, a patch panel of 26 pairs of outlets and plugs appeared, which additionally replaced the plaintext characters after basic encryption on the drums. This was a purely military improvement - this was not available on commercial versions. The long-term encryption key, which was formed by the disk commutation due to the permutation of 26 elements, is astronomical 4x1026 options! Now the software capabilities of a computer make it easy to enumerate such a number of options, but for the 30-40s it was unlikely and for a long time. The encryption picture was also complicated by a set of five Enigma disks (they were all different) of which only three were installed on the device at a time. They can be shuffled in any order, that is, there were a total of 10 installation options for one machine. A one-time key to get started offered 26 variants of symbols for each disk, and for three already 26 ^ 3 = 17576. And finally, the regularly changed plug-in panel switching scheme made the work of the cryptanalytic services of the enemies of Nazi Germany very difficult. Later, additional drums were added to the design. However, despite this, "Enigma" learned to "read" fully at the very beginning of the Second World War.
Some of the best cryptanalysts before the Great War were the Poles. Even during the civil war in Russia and the Soviet-Polish conflict, the Poles successfully decoded messages from the Soviet army and diplomats. Thus, the 2nd department (cryptanalysis) of the Polish General Staff in August 1920 "translated" from encrypted into Polish 410 telegrams signed by Trotsky, Tukhachevsky, Guy and Yakir. Moreover, during the offensive of the Red Army on Warsaw, the Poles misled Tukhachevsky's troops, which forced him to retreat to Zhitomir. Over time, the natural interest of Polish cryptanalysts shifted to an alarmingly gaining power in Germany. The Polish Bureau of Ciphers was at that time a fairly effective structure and included four departments:
- the Polish cipher unit, responsible for the protection of state communication lines;
- subdivision of radio intelligence;
- division of Russian ciphers;
- a division of German ciphers.
Saxon Palace in Warsaw, where the General Staff and the Bureau of Encryption were located. Photo of 1915. Source: photochronograph.ru
This is largely why it was the Poles who achieved the first successes in deciphering the Enigma. Since about 1926, they began to intercept German messages on the air, encrypted in a previously unknown way. A little later, in 1927 or 1929, an attempt was made to smuggle a box with Enigma into the German diplomatic consulate through customs from Germany. How did this happen and why did the Germans not send the apparatus through a closed diplomatic channel? No one will answer this now, but the Poles have studied in detail the device's device - this was done by the guys from the AVA radio engineering company, which has long worked with Polish intelligence. After careful acquaintance, Enigma was handed over to unsuspecting German diplomats. Of course, setting up a commercial version of the encryption machine could provide little to Polish cryptanalysts, but a start was made. Every year the Poles strengthened their service for "cracking" German codes - in 1928-1929 at the University of Poznan they organized courses on the study of cryptography for mathematicians with knowledge of the German language. Among the talented students, three stood out: Mariann Razhevsky, Heinrich Zygalsky and Jerzy Razitsky.
Marianne Razewski is a leading cryptanalyst in pre-war Poland. Source: lifeofpeople.info
All of them were subsequently taken into the special services, and they were the first to receive the results on the deciphering of the Enigma. In many ways, it was the Poles who were the first to understand the importance of attracting mathematicians for cryptanalysis of enemy ciphers. In general, in the 1920s and 1930s, Poland was almost a world leader in the field of cryptography, and specialists were often invited to share their experience in other countries. Observing the limits of secrecy, of course. Jan Kowalewski, a captain of the Polish army and a special on codes, traveled to Japan for this purpose, and then worked with a group of students from this country in his homeland. And he raised Rizobar Ito, a major Japanese cryptographer, who opened the English Playfair cipher system, which was used in the 30s on British communication lines. A little later, another potential enemies of Germany, the French, began to help the Poles.
