World War Two Background

World War Two, was fought between two different factions. The Axis Powers:  Italy, Japan, and Germany; and the Allied Forces:  China, Great Britain, France, Russia, and the United States. Russia began as a member of the Axis Powers, but when Germany broke an agreement made before the war, Russia joined the Allied Forces. The U.S. joined the war when Pearl Harbor was attacked on December 7th, 1941. 

During WWII, civilian communications, in general, were usually sent by letter.  The military, on the other hand, used radio signals and codes. Sending these messages was not as easy as it is today.  These coded messages could be easily intercepted.   Deciphering these codes would provide an advantage in the war.