The Enigma cipher machine is a cipher machine used to encrypt and decrypt files. Enigma is a collective name for a series of similar rotary machine encryption and decryption machines used by Nazi Germany during World War II. It includes many different models. Stream encryption for symmetric encryption algorithms in cryptography. Of all the versions of the Enigma cipher machine, the most famous is the military version used by Germany. Despite the high security of this machine, Allied cryptographers still Successfully deciphered a large number of messages encrypted by this machine. Allied intelligence called the deciphered code ULTRA, and ULTRA greatly helped Allied forces in Western Europe. There are still debates about how much ULTRA contributed to the war, but it is generally believed that the victory of the Allied forces in Western Europe can be advanced two years, which is entirely due to the successful deciphering of the Enigma cipher machine.