The reverse of the coin presents a conventional labyrinth of connections referring to the operation of the Enigma encryption machine. On the obverse there is an image of an eagle established as the national emblem of the Republic of Poland. In the background there is a stylized scheme of operation of the Enigma cipher machine. The Enigma was a German portable, electromechanical encryption machine whose operation was based on the principle of rotating rotors. During World War II, the Enigma was used by the armed forces and other state services of the Third Reich. Therefore, breaking the Enigma cipher, which could give the Allies an advantage, was strategically and psychologically important. Western countries considered it impossible to break the Enigma and completely abandoned the work on breaking it; French intelligence forwarded the Enigma plans acquired around 1931 by French agent Hans-Thilo Schmidt to the Poles, treating this information as worthless. The breakthrough came in December 1932, when the Poles managed to break the Enigma code. Then, in February 1933, a copy of the German encryption machine was ordered from the AVA Radio Factory. Since then, Poles were able to read German correspondence, although it was not easy, as the Germans were constantly improving both the machine and the encryption methods. Thanks to the work of Polish and later also British cryptologists, and thanks to the copies of the Enigma intercepted in the meantime, at the end of the war practically all the correspondence encrypted with it was read out by the Allies. This, in turn, made it possible to fight more effectively at the front; for example, it contributed to the annihilation of German submarines.