From: court@newton.physics.mun.ca (J. Lewis)
Subject: Re: Enigma Codes and Alan Turing
Summary: Some references
Organization: Memorial University of Newfoundland
Date: Sun, 11 Oct 1992 19:33:38 GMT


>Quote from I.J. Good ...

>It obviously could not be sufficient to merely simulate the Enigma
 ...
> So there had to be some further ingenuity in the bombe. This
> I cannot describe, but I can only say that Gordon Welchman had one
> of the basic ideas and Turing another one. My impression is that
> Turing's idea was one that might not have been thought of by anyone
> else for a long time and it greatly increased the power of the 
> bombe.

Details on the early successful attacks on Enigma can be found in
Gordon Welchman's book, "The Hut Six Story", 1982 (McGraw-Hill),
and, on the Polish side, "Enigma: How the
German Machine Cipher was Broken, and How it was Read by the Allies
in World War II", by Wladyslaw Kozaczuk, University Publishers of
America, ISBN 0-89093-547-5, translated from the Polish original of
1979.  See in particular the appendix by Marian Rejewski in Kozaczuk's
book.  

The Poles broke into German military Enigma very early on, about
1933 [neither of the books mentioned above are available to me
at this moment, so I am relying on memory], but didn't make this known
to the French and British until 1939.  After the fall of Poland, the
Polish cryptographic team escaped to France, and continued to operate under
the aegis of French intelligence - continued, in fact, for several months
even after the fall of France, in a remote location.

The German cryptologists from time to time made the Enigma ciphers more
elaborate and more secure, and this in turn required a great increase
in computing power, and, apparently, some very good ideas, to continue
to break the ciphers.  So far as I have been able to find, these
"good ideas" have never been made public, although the names of some
of them have been - the "Turingismus" for example.  I have the impression
that "we the public" have negligible information about the techniques
used to break the Enigma ciphers from about 1942 on.

Much information on "practical cryptography" - the theft of code books
and machines etc, on the various cryptographic agencies, and on the
handling of the product - Ultra - can be found in '"C": the Untold Story
of Sir Stewart Graham Menzies', by Anthony Cave Brown, MacMillan, 1987.
Brown has no understanding of the technical aspects of cryptography,
however.

The biography of Alan Turing mentioned by earlier posters is
"Alan Turing: the Enigma", by Andrew Hodges; Simon and Schuster;
ISBN 0-671-49207-1.

Two scholarly studies of particular interest in regard to Enigma/Ultra
are "Ultra and the West" (Hutchinson 1979) and "Ultra and
Mediterranean Strategy" (William Morrow and Co. 1989), both by Ralph
Bennett.  Bennett worked on the translation and interpretation of the
Enigma decrypts during the war, and, judging by the books, became
a thorough and careful historian afterwards.  He mentions that even
as late as the publication of the second book, the actual Enigma
decrypts were still classified, although their translations/interpretaions
were not.  His books touch on decryption, but are mainly concerned
with the interpretation, dissemination, use, and consequences of the
resulting intelligence.

John Lewis
Physics Department
Memorial University of Newfoundland

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