1928: ENIGMA Introduced into German Army
The number of mathematical permutations for every keystroke is astronomical. Allied forces were able to read most of the Enigma encrypted messages throughout most of the war as a result of the tireless effort of many Allied cryptologists. It is an electromechanical machine that used a combination of wired rotors and plugs to change each letter as it is typed. Today, many historians believe that the Allies' ability to read the Enigma-enciphered messages and act on that information shortened the war by as many as two years, saving thousands of Allied and Axis lives."
The Enigma exhibit (see link below) is one of the most popular exhibits at the National Cryptologic Museum. Updated in 2016, the exhibit features the history and development of several versions of the once thought unbreakable Enigma machine.
What makes this exhibit most unique, however, is that it includes authentic World War II Enigma machines that visitors can use to encrypt and decrypt their own messages.