Typex Encyphering Machine, Mark 22

Typex originated in an interdepartmental committee that started work in 1926 but by 1933 had achieved little. Frustrated, Wing Commander Lywood went his own way and investigated developing two commercial Enigma machines that had been purchased by the Admiralty for evaluation. He worked with Creed & Co and a first prototype was delivered in April 1935 with the first Mk1 machines delivered in early 1937. The first machines were called ‘Enigma with Type X modifications’...later shortened to ‘Typex’. The machines were so similar to Enigma that at Bletchley Park, when the Enigma settings were discovered for a particular net, it was Typex machines that were actually used to do the decode. Similarly a small modifcation to Typex allowed it to communicate with the US Sigaba machine. There are many similar connections to machines of that time and post-war....for instance the Russian 'Fialka' machine (in use until the end of the Cold War) was based on an Enigma. This is part of the reason why it all remained so secret for so long. The Germans captured at least two Typex machines, the first at Dunkirk (less rotors) and a later one that was actually converted into an Enigma by a maintenance engineer to give himself a spare unit. The Germans never broke into Typex.

The story of Enigma is now well documented in histories concerning codes and cyphers but its British counterpart, a machine-based encoder called Typex, is less well-known. Enigma was adopted by the German Navy in 1926, by the German Army in 1928 and by the Luftwaffe in 1934. The British were also considering the replacement of book systems by cypher machines and in 1928 two commercial Enigma machines were purchased as an Admiralty initiative (they were readily available, advertised in the Daily Telegraph). It was not until 1935 however, that it was decided that the Air Ministry should arrange for the construction of three sets of cypher machines of an improved 'Enigma' type. The Air Ministry commissioned Creed & Company, a commercial teleprinter manufacturer, to produce copies of the commercial Enigma. By March 1936 Creeds had made two copies which became known as the 'RAF Enigma with Type X attachments', subsequently truncated to 'Typex'. The Air Ministry adopted Typex before the outbreak of war and by September 1939 it was in use at all RAF HQs. It proved to be completely secure for more important RAF ground-to-ground communications throughout the war. The War Office adopted Typex before the war and by September 1939 this system, which remained secure throughout the war, was in use between the War Office and commands at home and overseas and within commands down to division level. The most secret traffic sent through Typex to command level was Ultra, intelligence messages based on the results of decyphered German radio traffic encyphered by Enigma machines. Typex used 5 wheels or rotors; enigma machines had 3 or 4. Typex was not used at sea by the Royal Navy during the war but the Combined Cypher Machine (CCM) was used from November 1943 and it was eventually held by all HM ships. CCM was based on the US Electrical Cypher Machine (ECM) and the Typex. Typex had been made available to the US on their entry into the war, and by an agreement in June 1942 the US undertook to modify the ECM to work with Typex and to develop an adaptor for the latter. The modified ECM and Typex machines became different marks of the CCM. Like Typex, CCM proved to be totally secure and the Germans made no serious attempt to solve either system. Typex machines remained in service after the war until they were replaced by modern machine systems in the early 1960's, after no less than 30 years of service.

Mark 22 British Typex encyphering machine