The History of Hut Eight

In fact the only valuable acquisition during this period was the finding of wheel 8 in August 1940, the last new wheel to be introduced during the war.

The next event in the cryptographic world was the breaking in November of May 8th, known to history as Foss' day. Foss had joined temporarily to assist in exploiting the Banburismus idea and after a labour of many months broke the first day on Banburismus. The moral effect of this triumph was considerable and about a fortnight later another Banburismus, April 14th, was broken at what was considered lightning speed. June 26th was also broken (June having by now been established to be on the same bigram tables) and contained the information that new bigram tables would come into force on July 1st, so Banburismus after that date was out of the question.

A second sensational event was the breaking of April 28th on a crib, the first all wheel order crib success. Hut 8 at this time contained no linguists and no cribster by profession and the crib was produced as a result of the labour of two mathematicians who take great delight in recalling that the correct form of the crib had been rejected by the rival Naval Section cribster.

This last break was obtained in February 1941 and was followed shortly afterwards by the first Lofoten pinch which is one of the landmarks in the history of the Section. This pinch gave us the complete keys for February - but no bigram tables or K book.

The immediate problem was to build up the bigram tables by EINSing and twiddling, the methods for which had now been much improved. With a whole month's traffic to deal with, there was a vast amount of work to be done and the staff position was acute. Rapid expansion and training of new people had to take place and greatly slowed up the work but by late in March the bigram tables were more or less complete.

Much of the theory of the Banburismus scoring system had been worked out at the end of 1940 and now statistics were brought up to date and satisfactory charts produced. Much work was done on the identification and utilization of dummy messages which at this time formed about half the traffic; it was most important to know and allow for the chance of a message being dummy; the end of a dummy message consisted of a string of consonants and yielded a totally different repeat rate: if dummy was not allowed for, Banburismus could become difficult and even insoluble.


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