Editing Typex (section)

==Security and use==
Less than a year into the war, the Germans could read all British military encryption other than Typex,<ref>{{Citation | last = Comer | first = Tony | title = Commentary: Poland's Decisive Role in Cracking Enigma and Transforming the UK's SIGINT Operations | publisher = [[Royal United Services Institute]] | year = 2021 | url = https://rusi.org/commentary/poland-decisive-role-cracking-enigma-and-transforming-uk-sigint-operations }}</ref> which was used by the British armed forces and by Commonwealth countries including Australia, Canada and New Zealand. The [[Royal Navy]] decided to adopt the RAF Type X Mark II in 1940 after trials; eight stations already had Type X machines. Eventually over 600 machines would be required. New Zealand initially got two machines at a cost of £115 (GBP) each for Auckland and Wellington.<ref>RN circulars M 0707/40, 1 May 1940 and M 013030/40, 26 July 1940 on Archives NZ RNZN file R21466809</ref>

From 1943 the Americans and the British agreed upon a [[Combined Cipher Machine]] (CCM). The British Typex and American [[ECM Mark II]] could be adapted to become interoperable. While the British showed Typex to the Americans, the Americans never permitted the British to see the ECM, which was a more complex design. Instead, attachments were built for both that allowed them to read messages created on the other.

In 1944 the Admiralty decided to supply 2 CCM Mark III machines (the Typex Mark II with adaptors for the American CCM) for each "major" war vessel down to and including corvettes but not submarines; RNZN vessels were the ''[[HMNZS Achilles (70)|Achilles]]'', ''[[HMNZS Arabis (K385)|Arabis]]'' (then out of action), ''[[HMNZS Arbutus (K403)|Arbutus]]'', ''[[HMS Gambia (48)|Gambia]]'' and ''Matua''.<ref>RN circular AFO S 7/44 on Archives NZ RNZN Naval file R21466810</ref>

Although a British test cryptanalytic attack made considerable progress, the results were not as significant as against the Enigma, due to the increased complexity of the system and the low levels of traffic.

A Typex machine without rotors was captured by German forces at [[Dunkirk]] during the [[Battle of France]] and more than one German cryptanalytic section proposed attempting to crack Typex; however, the ''[[B-Dienst]]'' codebreaking organisation gave up on it after six weeks, when further time and personnel for such attempts were refused.<ref>{{cite book| last1=Ferris| first1=John| title=Intelligence and Strategy: Selected Essays|  date=7 May 2007| publisher=Routledge|  isbn=9781134233342| page=165| url=  https://books.google.com/books?id=zC1-AgAAQBAJ&pg=PA165}}</ref>

One German cryptanalyst stated that the Typex was more secure than the Enigma since it had seven rotors, therefore no major effort was made to crack Typex messages as they believed that even the Enigma's messages were unbreakable.<ref>{{cite book | last = Ratcliff | first = Rebecca Ann | title = Delusions of Intelligence | publisher = Cambridge University Press | year = 2006 | pages = 165 | isbn = 0-521-85522-5}}</ref>

Although the Typex has been attributed as having good security, the historic record is much less clear. There was an ongoing investigation into Typex security that arose out of German POWs in North Africa claiming that Typex traffic was decipherable.

A brief excerpt from the report

<blockquote><poem>TOP SECRET U [ZIP/SAC/G.34]
THE POSSIBLE EXPLOITATION OF TYPEX BY THE GERMAN SIGINT SERVICES

The following is a summary of information so far received on German attempts to break into the British Typex machine, based on P/W interrogations carried out during and subsequent to the war. It is divided into (a) the North African interrogations, (b) information gathered after the end of the war, and (c) an attempt to sum up the evidence for and against the possibility of German successes.

Apart from an unconfirmed report from an agent in France on 19 July 1942 to the effect that the GAF were using two British machines captured at DUNKIRK for passing their own traffic between BERLIN and GOLDAP, our evidence during the war was based on reports that OKH was exploiting Typex material left behind in TOBRUK in 1942.</poem></blockquote>

Typex machines continued in use long after World War II. The [[New Zealand]] military used TypeX machines until the early 1970s, disposing of its last machine in about 1973.<ref>{{cite web | last =Mogon | first=Eric | title=Chapter 8-A History of Communications Security in New Zealand/ Codes & Cyphers in World War 2  | work =Unofficial RNZN Communications History    | publisher = RNZN Communicators Association | url =http://rnzncomms.org/ourhistory/chapter8/  | access-date =28 December 2014}} ([http://rnzncomms.files.wordpress.com/2011/01/chapter-8-crypto-18-jan-11.pdf PDF version]-135 Kb)</ref>