Enigma: The Battle for the Code

There are two themes to this book, the methods used to break the German enigma machine cipher and the capture of code books that aided in this process. As such, the book contains both a lot of technical information on machine ciphering/deciphering and exciting chapters dealing with the capturing of German submarines and some surface ships; both are critical aspects of the story of how the German enigma messages were deciphered. The book focuses almost exclusively on the naval machine, which was both more technically complex and utilized more complex encoding procedures than that of the German Army and Air force machines. The breaking of the naval code was made easier by the ability to capture code books from submarines and small surface ships (weather ships, trawlers, etc.). This, as is discussed in the book, was a two edged sword, as the whole enigma deciphering program might be placed in jeopardy if the Germans learned of these captures. Fortunately, the Germans believed that even such captures would be of only modest value because of the complexity of the machines and the procedures that were employed. At most, it was believed that code books would be of only short-term value, since the machine settings and tables were frequently changed making a stolen code book soon obsolete. The Germans did not realize that Polish and then British mathematicians had uncovered weaknesses in the enigma system, and that these weaknesses allowed the ciphers to be broken even without code books (although at times these code books were invaluable). This book explains how this was done, both in the body of the text and at greater length in a series of appendices. (This aspect of the book is very complex and technical, which some readers might find a bit tedious and off-putting.) The book also tells the exciting stories of very brave British sailors (and some Americans) going down into sinking submarines to retrieve code books and enigma machines, all the while aware that scuttling charges might go off killing them outright or trapping them in a very much more rapidly sinking submarine (from which they would not be able to escape); indeed some did not escape. Some of the book also focuses on spies and counter spies and how a German sold the secret of the enigma machine to the French, how this aided the Polish code breakers before the start of the war, the subsequent German attempts (mostly successful) to capture the French and Polish code breakers, and finally why they did not learn enough from these captures to stop using the enigma machines. As noted, this is largely the story of British code breakers, working on the German naval ciphers. There is some reference to work with the Americans and work on other German ciphers. I recommend Budiansky's Battle of Wits for information on the American collaboration with the British, efforts of the British and Americans to break the German Army and Air force enigma machines and the American work on Japanese

I recently became interested in the history of World War II. I was looking for a good book about the subject to read and I stumbled upon this one. Also having a degree in computer science and mathematics I decided this was the book for me. I have never read a history book like this before and wasn't really sure how I would like it. So far I have absolutely loved it. You would expect the pacing and dialog to be very slow and boring but that is not the case at all. This book has held my interest thoroughly from the start.

Once I picked this book up, it was very hard to put down. Sebag-Montefiore has compiled a gripping glimpse into the code breaking efforts by the British. His source and reference material are outstanding and his explanations of the technical aspects are gentle enough for the non-cryptologist to follow. I felt his technical analysis was just right, enough to let me understand the problems the Bletchly Park code breakers faced, while not to technical for me to lose interest.Those wanting a in depth review of the methods used may want to look elsewhere, but I believe this book details the human story behind Bletchly Park's success masterfully. It's amazing to me that despite the capability of the Enigma machine, its ultimate Achilles heel was that it was operated by humans, who are in the end non-random and prone to habit. The eccentricities of the code breakers, the stiff British upper lip, and the maverick attitude of the US code breakers are all displayed for the reader.The exploits of the Royal Navy is nothing short of truly heroic in their efforts to obtain code books to aid Bletchly's cause. It's ironic that the Enigma was first broken by three Polish mathematicians, who have never received much credit. A fascinating book on exploits that had far reaching consequences after the end of WWII. Strongest recomendation.

This is an excellent history of code breaking during World War II. The majority of the book is from the British perspective. It is action packed. If you are looking for the math behind the code breaking, this is not the book. Some key points are:-Code breaking of enigma much sooner than I had known.-Steps that the Germans took to "secure" their code often backfired and made it easier to break.-We are all human. Human habits were key to breaking the codes.-The code breaking was a key weapon in WWII.This book whet my appetite. I hope the author writes more. Possible topics include:-German code breaking. Too many teasers in this book about the German code breakers.. I want more details.-US code breaking of Japan and Germany.-The hints of the French activity left me wanting to know more.Overall I enjoyed the book. I would recommend it to history buffs and math buffs (too few books where mathematics and mathematicians are the heros.)

In last year's film _U-571_, tribute was paid to those American heroes who were able to grab a Nazi Enigma encryption machine, thereby enabling the allies to break enemy messages and win the war. _U-571_ showed the American heroes capturing Enigma, when in truth it was British heroes who did so, and not just once. Nonetheless, the film did demonstrate the continuing realization of the importance of the cracking of Enigma, the most famous episode of codebreaking in history. The story of the English boffins at Bletchley Park, led by the strange, brilliant, and doomed Alan Turing is indeed one of the great victories of the war.But it wasn't all mathematicians, primitive computers, and brainpower. _Enigma: The Battle for the Code_ (John Wiley & Sons) by Hugh Sebag-Montefiore tells plenty about the cerebral efforts within Bletchley Park, but expands the story to include the cloak-and-dagger work and military captures of German vessels that were able to bring codebooks, Enigma machines, and encoding wheels into the purview of the cryptographers. The victory over Enigma is a thrilling story that first started being revealed only twenty years ago, and this book helps to describe the difficulties the decoders went through because of the hazards of getting information from the field. And it is a good story, with hair-raising escapes, bureaucratic in-fighting, eccentric characters, and genuine heroism on the high seas.Some of the spywork was mundane. We owe a lot to Hans Thilo Schmidt, for instance, the German who spied for the French Secret Service, providing keys to the system as early as 1931. Schmidt was, however, no hero; he was simply in it for the money, to pay for vacations and mistresses. He continued to provide information for pay until caught by the Germans in 1943. Captured, he took cyanide, perhaps provided by his family and perhaps allowed by his captors to avoid an embarrassing trial. His story has not been told before, and came from sources previously unavailable to historians._Enigma_ gives a chronology of the battle for the codes that demonstrates how vital decryption was in winning the war in the Atlantic. When Bletchley Park could decrypt quickly, information got to the convoys enabling them to avoid U-boats. When the Nazis changed methods of using Enigma, information slowed and ships were lost. The ups and downs of gaining information from spies or from captured ships and using that information to crack messages is well told here. The victory over Enigma is rightly remembered and celebrated. Sebag-Montefiore expands the extent of the victory beyond the Bletchley cerebrations to the mostly unsung heroes who gave the code-crunchers something to work on. The book is full of information, including appendices on details of how the Enigma machine worked and a useful chronology of high points in the Enigma battle. It is a vivid account of the battles at sea and on land that won the code war.