A memoir by one of the key mathematicians who worked on cracking the Enigma code at Bletchley Park.
This explanations of the cryptanalysis is by and large too difficult for me and I suspect that my understanding of maths is significantly higher than the average reader. The history is mostly (and avowedly) written from memory; very little research has been done (or could have been done given that this book was written while Enigma was still top secret). The prose style is pedestrian: my heart sank when he explained that there had been ten steps in his thinking and he would now proceed to explain them one by one. There are times when, like most memoirs, his concern is with ensuring his own place in history and there are therefore moments when he self-indulgently takes issue with authors having an alternative point of view.
Having just watched a television programme about Mr Welchman and his Enigma success on the BBC I had some idea of what he had been doing. He was instrumental in what is now called Traffic Analysis (though he suggests that he was not the prime mover here, nor was it the most important aspect of his work) in which the German military machine was tracked by knowing which radio operator was broadcasting from where and at what times, regardless of the content of the message. Because much of the radio broadcasts contained routine parts (the full military title of the commander sending the message and of whoever was to receive it, often a weather report, often a comment saying something along the lines of 'nothing to report') 'cribs' could be constructed in which cryptanalysts would scour a coded message for such routine parts and try to deduce the key from that. I learned that every Enigma message contained an unencrypted part and that part of this explained the key settings that the individual Enigma operator was using; since at the start this 'indicator' was given twice it provided an 'in' for the cryptanalysts (although I couldn't understand the explanation for this).
One gets quite a clear picture of Mr Welchman. During the war he often had a chauffeur driven car and he lived in a mediaeval priory. One guesses that he was quite posh before he became a Cambridge fellow!
So there was a lot of interest in this for the specialist but I struggled with the style. One day someone will be able to explain Enigma to me but this book certainly came nowhere near doing that.
September 2015; 249 pages
A better (but still not perfect) explanation of Enigma is given by Alan Turing: the Enigma by Andrew Hodges
Showing posts with label Enigma. Show all posts
Showing posts with label Enigma. Show all posts
Monday, 14 September 2015
Sunday, 11 January 2015
"Alan Turing: the Enigma" by Andrew Hodges
This is a very thorough, indeed exhaustive, biography of Alan Turing and his ideas. It is the book that has been filmed as the Imitation Game
Turing (most people apart from 'Alan' and his closest associates are referred to either by their surnames or by their initials and surnames like a cricket card) was not a particularly distinguished school boy who had a particular love for Maths but took two goes to get a scholarship to Cambridge. He seemed to go from zero to infinity as an undergraduate and before his doctorate published his ground breaking work on the Universal Turing Machine. Then he was recruited to code breaking and solved the secrets of the naval Enigma machine so saving Britain's convoyed food supplies (and many thousands of sailors) during the Battle of the Atlantic. But after the war he failed to have much of an impact on the birth of the primitive computers despite working at the NPL (where he met my father) on the ACE and at Manchester University. He wrote a truly ground-breaking paper on morphology but this was mostly unrecognised at the time. Then he was arrested and convicted of homosexuality and forced to undergo hormone therapy as an alternative to prison. Some time after that ended he died from cyanide poisoning.
This is a difficult biography to write. Turning's work was in the hardest bits of mathematics and logic and I found the explanations hard to understand. (And I think I might have a small edge of a general reader, having taught Physics for 33 years.) There is much that is mysterious. His wartime work was under conditions of the strictest secrecy but so was his sex life (being criminal at that time) and so was his death (was it suicide? if so, why? - he left no note - or was it an an accident? or was he, as the conspiracy theorists suggest, murdered by the security services who in the height of the Cold War were frightened that this gay man might spill wartime secrets?). Hodges has done well to tell us as much as he has.
But there was an awful lot of speculation. Hodges tends to assume that Turing's scientific ideas mostly come from a text book he had as a child; there are many quotes from it. Other major influences are a book by Eddington and Back to Methuselah by George Bernard Shaw. There is a lot of talk about Red Queens and White Queens and chess problems and Alice Through the Looking Glass. But there seems little evidence for most of this.
I think this book would have benefited from a severe pruning. Although the book leaps over the last year of his life and dismisses non-suicide theories of his death, it then spends 50 pages discussing the invidious position of homosexuals in Cold War Britain. There is an awful lot of detail on the early days of computing in Britain. It could have been shorter and tighter and this would have been better.
And it really isn't for the general reader.
January 2015; 656 pages
Turing (most people apart from 'Alan' and his closest associates are referred to either by their surnames or by their initials and surnames like a cricket card) was not a particularly distinguished school boy who had a particular love for Maths but took two goes to get a scholarship to Cambridge. He seemed to go from zero to infinity as an undergraduate and before his doctorate published his ground breaking work on the Universal Turing Machine. Then he was recruited to code breaking and solved the secrets of the naval Enigma machine so saving Britain's convoyed food supplies (and many thousands of sailors) during the Battle of the Atlantic. But after the war he failed to have much of an impact on the birth of the primitive computers despite working at the NPL (where he met my father) on the ACE and at Manchester University. He wrote a truly ground-breaking paper on morphology but this was mostly unrecognised at the time. Then he was arrested and convicted of homosexuality and forced to undergo hormone therapy as an alternative to prison. Some time after that ended he died from cyanide poisoning.
This is a difficult biography to write. Turning's work was in the hardest bits of mathematics and logic and I found the explanations hard to understand. (And I think I might have a small edge of a general reader, having taught Physics for 33 years.) There is much that is mysterious. His wartime work was under conditions of the strictest secrecy but so was his sex life (being criminal at that time) and so was his death (was it suicide? if so, why? - he left no note - or was it an an accident? or was he, as the conspiracy theorists suggest, murdered by the security services who in the height of the Cold War were frightened that this gay man might spill wartime secrets?). Hodges has done well to tell us as much as he has.
But there was an awful lot of speculation. Hodges tends to assume that Turing's scientific ideas mostly come from a text book he had as a child; there are many quotes from it. Other major influences are a book by Eddington and Back to Methuselah by George Bernard Shaw. There is a lot of talk about Red Queens and White Queens and chess problems and Alice Through the Looking Glass. But there seems little evidence for most of this.
I think this book would have benefited from a severe pruning. Although the book leaps over the last year of his life and dismisses non-suicide theories of his death, it then spends 50 pages discussing the invidious position of homosexuals in Cold War Britain. There is an awful lot of detail on the early days of computing in Britain. It could have been shorter and tighter and this would have been better.
And it really isn't for the general reader.
January 2015; 656 pages
More scientific biographies, reviewed in this blog, may be found by clicking here.
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