During World War II Nazi Germany primarily encoded its messages through the use of what was known as the "Enigma" machine. Enigma’s use by the Wehrmacht stretched back to the early 1930s and originated from a design created by Hugo Alexander Koch in the Netherlands.
Although heavily modified prior to the Second World War’s onset, the Enigma machines used in 1939-1945 remained similar to Koch’s prototypes from two decades prior. For a variety of reasons the Enigma machine was extraordinarily difficult to crack.
