Computers that were widely used during the First World War (some governments began to use them in the 195s and 196s; Other organizations have no personal use records ten years later or before 1975), which makes the multi-letter substitution password widely used by machinery. Several inventors had similar ideas at the same time. In 1919, there were four patent applications for rotating disk (English: Rotor machine). One of the most important and famous is the Enigma cipher machine used by the German Defence Forces in 193s. At the same time, the Allies also had their own encryption systems: Sigaba (English: SIGABA) in America and Typex (English: Typex) in Britain.
they are similar in that they both use mechanical rotating disks for encryption. Because more than one rotating disk is composed of ciphertext, if each word is equipped with a symbol, the amount of symbols will be higher than astronomical figures. However, early versions of these machines are easily cracked. William F.Friedman of Signal Intelligence Service (English: William F. Friedman) discovered the flaw of Hepburn rotator (English: Hebern_Rotor_Machine) at an early stage; Dillwyn Knox (English: Dillwyn Knox) of Government Cryptography School (English: GC%26CS) cracked the version of Enigma cipher machine without wiring board before World War II. The military version of Enigma cipher machine can only be cracked by the analysts of Bletchley Garden at a later stage, which was inspired by Polish mathematician Marian Rejewski.
messages encrypted by p>SIGABA and Typex have not been cracked so far.