In This Review
Kahn On Codes: Secrets of the New Cryptology
Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two
Alan Turing: The Enigma
Taken together, these three books put in fascinating perspective the contribution of Polish cryptanalysts to the solution of the high-level German Enigma cipher (ULTRA) in World War II. Kahn's collection of his recent writings contains many nuggets; the foremost is his careful account of the German agent who, via the French, provided the Poles with material that greatly (perhaps crucially) assisted their initial breakthrough in 1932. Kozaczuk, drawing on earlier Polish revelations, contains the fullest account of the Polish achievement, how it was handed over to the British in July 1939, how the Poles, French and British worked together in 1939-40-and the magnificent performance of the Poles and French who remained in France after 1940 and kept the secret intact. The book, originally published in Polish in 1979, is supplemented by useful appendices which, among other things, take account of W.G. Welchman's book on Enigma (The Hut 6 Story, reviewed in Foreign Affairs, Spring 1982).
The Turing biography, by a fellow mathematician, contains a full account of how the British went on to master more complex Enigma variations introduced just before and during the war, and to apply related techniques to other advanced German systems. Credit is judiciously allocated, and on Enigma itself Turing's contribution must clearly be set alongside that of Welchman; to this observer (and later participant) both accounts lead to the conclusion that the original British debt to the Poles was much greater than the official British history of intelligence (F.H. Hinsley et al., 1979) has acknowledged-but also that the Poles and French could never have matched the assembled brains and technical skills of the British. Enigma is only a small part of a well-written life of a legendary mathematician and computer pioneer, dogged by the tragedy of being an avowed homosexual in an uncomprehending time.