The original Enigma was a german cryptographic tool, used for coding army messages. Invented by H. Koch, was in use since 1920's. The coding method Enigma used was not broken till three Polish mathematicians: Marian Rejewski, Jerzy Rozycki and Henryk Zygalski started working on it shortly before WW2. Thanks to their accomplishment, the Allies were able to read top-secret Nazi communication.
The Enigma cipher machine had the confidence of German forces who depended upon its security. Initially broken by Polish cryptanalysts, Enigma decrypts from British and later American efforts were given the cover name ULTRA to reflect the value of the information.
Dr A. Ray Miller