– Marconi’s wireless radio was used on dreadnoughts, in a few years all navies were using it. Prior to this the only way to get a message to a ship was by ship. For this reason radio transformed naval warfare, used in the WWI
– Magdeburg ship – 26 August 1914 ran aground in mist 1 mile off course, Gulf of Finland, Russians arrived, found principle code book and passed one copy to Britain, which went straight to Room 40. (on 11 October 1914 the Australian navy seized a copy from the Hobart)
– Room 40 established October 1914
– Because German cables were cut, Germans had to use wireless, but also used cables of Sweden and US used by Germany. Wednesday 17 January 1917 – German diplomatic telegram sent by FM of Germany to German diplomat in the US, bound for Mexico, full text given to Wilson and by April US was in the war. Code breakers were a decisive secret weapon in bringing the US into war.
– Winston Churchill revealed in his memoirs, The World in Crisis – published 1923 – the role code breaking played and the Mangdeberg and this stunned the Germans. Karl Dernz, U-boat commander in WWI had seen how close the U boats had come to breaking the blockade, he said never again would German codes be broken again.
– Herbert Yardley has been to Room 40 during WWII
– The Poles had the best code breakers after the WWI, had broken Russian codes, focused on German code and in the decade following the war could read almost all.
– On 15 July 1928 German signals changed = unreadable.
– Ciphers are different to code – a cipher replaces every word or letter with another alphabet
– The Polish had three German speaking mathematicians who tried to decode enigma,
– 1932 Captain Betrand had someone called “ash” walked into his office offering to act as a spy, a walk in is suspicious but he told him he had documents he wanted to trade for cash. In 1932 he gave the instruction manual for enigma. He got 10,000 marks for it. This material went to the Poles, not the British
– 15 December 1938 Poles couldn’t read again because the Germans had added 2 new rotors – when the Poles had just passed information on to the French and the British, but it went dark again
– Bletchley Park, established late August 1938
– November 1921 – international disarmament conference in DC re naval power between Japan, US and UK, establishing tonnage – the Japanese wanted parity but the US threatened by this,
– The US Cable companies were convinced to pass on codes from Japan – and yardley was called in to help – and he delivered, unbeknownst even to the President, Yardley was set up on East 37th NY, paid by a secret slush fund. He couldn’t even read Japanese but with only a few days to break the code, he did and learned that Japan was given instructions to capitulate if their demands for parity of naval power would cause too much frictions, so the Japanese agreed to half tonnage only.
– In 1929, Stimson found out about the American Black Chamber, and said “gentlemen don’t read each others mail” and shut it down, no pension, because unofficial, so he wrote a book, Japan outraged, like the Germans upon reading Churchill, sought unbreakable codes by machine
– William Friedman hired by US Army to replace Yardley, he employed Rowlett to be a cryptanalyst, a word he made up
– Japan had built a lot of tonnage in 10 years, so US began to extend the Pacific Fleet
– Friedman was able to decode the Japanese communications, but then in 1938 could no longer read and realised their high grade diplomatic traffic was now encrypted by machine – Purple was the name given to the new code machine
– Japan’s increasing belligerence caused urgency to break purple. They used IBM tabulating machines adapted by Friedman to try to build a replica of Purple. He created 2 typewriters wired together, worked out that Japan divided the month into 10 day periods, used 1st day with predictable changes
– in early December an order came through to destroy all Purple machines except those in DC. On 6 December, a message was sent to the German embassy in the US but decoded too late – the dawn mentioned was dawn in teh pacific, = 7 December Pearl Harbour
– JN 25 – Japanese navy code – the name given to the code of Japan after Pearl Harbour, couldn’t be decrypted. Purple was the diplomatic code, but JN 25 more difficult because fewer intercepts, numerical, 45,000 numbers that linked to words, 5 random numbers were added to random numbers, IMB tabulating machines were used
– Operation MO was discovered by decrypting the codes, that was the invasion of Port Morseby from which to invade Australia. May 1942 battle of the oral sea
– 10,000 people at Bletchley by the end
– All German communications had “the enemy is listening” on them
– London saw US as having a ruthless press and open like a child’s piggy bank = but were invited into Bletchley and enigma not leaked
– Enigma teams got to know German operators, used girlfriends names, slang, and swear words, got familiar with the traffic, because each key was assigned to a different individual to get to know the habits and idiosyncrasies and how they chose their indicators
– U/10 – 1941 raid – boarded a trawler and found enigma rotor wheels, got a cipher shedules on one shift, so had a narrow window, captured another ship – and Operational U boat captured U-100 had a whole enigma machine.