In wartime, governments and armed forces must often share secret information about plans and operations. The challenge is to keep these communications secret from the enemy. This is usually done by putting confidential information into code, making it meaningless to anyone without a code breaker.
The Enigma machine contained many cogs and wheels, which could be set in different ways. Each setting produced a unique set of coded letters.
In World War II, the Germans used a very advanced code machine called Enigma. The machine encoded all communications sent from military headquarters to outposts in occupied Europe. Enigma used a series of rotating wheels to scramble messages into meaningless text. It contained billions of possible combinations, so if you didn’t know the Enigma setting, the message was impossible to figure out. To make things even harder, the code’s settings were changed every day.
At the start of the war, the British set up a team of expert code breakers to try to crack the Enigma code. They were based at “Station X” in Bletchley Park, Buckinghamshire. The initial team of four had risen to about 3,500 by the end of 1942, and about 9,000 by January 1945.
The Germans, with their orderly way of doing things, actually helped the code breakers since coded messages would often start with the words To the Group. Such repeated phrases were known as cribs and were a great help in cracking other parts of the code. The code breakers were also helped by the fact that no letter could be coded as itself, reducing the number of possible settings for Enigma. Using these clues, the code breakers succeeded in cracking the code on many occasions.
In the Pacific war between the United States and Japan, the US Marines frequently used Native Americans to send secret messages by radio or telephone. While ordinary codes can be broken fairly quickly, codes based on a unique language must be studied for a long time before being understood. The Japanese never cracked the spoken code. US commanders claim the United States would never have won the Battle of Iwo Jima without the help of the “code talkers.”
Two US Marine “code talkers” use their native Navajo language to send a radio signal during a battle in the Pacific war.