Possibly the most well known of all cipher machines is the German Enigma. It became the workhorse of the German military services, used to encrypt tens of thousands of tactical messages throughout World War II. The number of mathematical permutations for every keystroke is astronomical.
Lots of pics at the Virtual Enigma Museum.
Hi Joel, thanks for linking to my Enigma Sim. Have a visit to my weblog at http://www.rijmenants.blogspot.com
regards, Dirk