Typex Mark II
Britain’s principal cipher machine from 1937 through the 1950s. Based on the commercial
Enigma design but significantly improved with 5 rotors (2 static "stator" rotors acting as a
plugboard, 3 moving rotors), and crucially, a printing mechanism instead of a lampboard.
Encrypted output was printed directly onto paper tape.
Typex was adapted from the Enigma principle but was never broken by the Germans.
In 1943, it was modified to interoperate with America’s SIGABA via the "Combined Cipher
Machine" (CCM) protocol, enabling secure Anglo-American strategic communications. Over 12,000
Typex machines were produced. It remained in British service until the early 1970s.