The Battle For History by John Keegan

Author:John Keegan [Keegan, John]
Language: eng
Format: epub
ISBN: 978-0-307-36722-8
Publisher: Random House of Canada
Published: 1995-05-06T04:00:00+00:00

CHAPTER FIVE

THE BRAINS AND SINEWS

OF WAR

WAR, THOUGH ULTIMATELY ABOUT FIGHTING, is also about planning where and when to fight, and disguising one’s intentions from the enemy while seeking to penetrate his.

Commanders have always sought to deceive, and have put an equivalent effort into protecting themselves against surprise, chiefly through espionage and the interception of the enemy’s communications. In no war before that of 1939–45, however, had intelligence been accorded a greater importance. The rapidity of operations, vastly accelerated by the internal-combustion engine and the aeroplane, and the greatly enhanced destructive effect, particularly on civilian targets, of modern weapons lent unprecedented urgency to the search for fresh (“real time”) and accurate information. It lent equal weight to the need to hide the meaning and destination of signals, particularly since the scale and pace of the fighting necessitated ever greater dependence on the new medium of radio. Such factors are what allow us to talk about the Second World War as an “intelligence war.”

The greatest secret of the Second World War was that, from as early as 1940, the Western allies were reading the German secure radio ciphers, and, from 1941 on, were reading them extensively and in “real time.” The German armed forces had adopted in the 1930s a commercial cipher machine, the Enigma, as its instrument of encryptment; capable of 200 million possible transpositions for any single letter entered on its typewriter keyboard, it was believed to produce unbreakable encipherments. Work by the Polish intelligence service before 1939 had shown the belief to be false and, during the Phoney War, the work done by the Polish mathematicians was donated to the British and French teams also struggling with Enigma. After the fall of France, the British anti-Enigma attack was concentrated at the Government Code and Cipher School at Bletchley Park, to which were recruited first-class mathematicians, linguists, and other possessors of appropriate talents from Oxford, Cambridge, and similar centres of learning. They began to make rapid progress, partly by direct attack on the logicalities of the encipherment, partly by recognizing and exploiting mistakes made by the German users of the machine in day-to-day transmissions, Luftwaffe users were the least careful, and it was a Luftwaffe “key” that was broken first; breaks into the army and naval keys followed; but, it should be noted, some keys were never broken. Keys were also lost, sometimes for long periods, when Germans made changes or complexified the machine or tightened up procedures. The naval key was lost, with grave effects on the conduct of the Battle of the Atlantic, during 1942–43; all the graver was the loss because the German equivalent of Bletchley, the B-dienst (Observation Service) was meanwhile reading British naval signals, which were still being disguised inside an obsolete book code.

At the height of the intelligence war, ten thousand people worked at Bletchley. All were sworn to secrecy — and the secret was kept until 1974, when, for reasons which have never been fully explained, a former Bletchley initiate, Group Captain F.W. Winterbotham, was allowed to publish an undocumented account of Bletchley’s wartime work.

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