The Enigma was a cryptodevice used by the Germans before and                      
during World War II.  It was considered to provide unbreakable encryption.                  
In this talk, we explore the history of cryptology from 2000 years ago                      
through the mid-20th century, and learn what design principles went into the                
Enigma.  We will see how it operated and why the Germans had good reason to                 
believe that it was unbreakable.