The Code Book. The Evolution of Secrecy from Mary, Queen of Scots to Quantum Cryptography.

reviewed by Bob Bruen

Simon Singh. Doubleday 1999.
402 pages. 10 appendices, glossary, index, bibliography, illustrations. $24.95.
ISBN 0-385-49531-5. LoC Z103.S56.

For many reasons, there is a real, growing interest crypto. This latest book in the history of codes, ciphers and crypto is a welcome addition. For most of this century developments were kept secret from the general public in spite of the critical roles played by cryptographers and cryptanalysts. Cryptology has been important in gaining and keeping power through both intrigue and war for millennia. Today, of course, the battle is being waged for individuals to wield the same power over personal communications with the stakes as high as they ever were.

In the late 1500s, Queen Elizabeth was able to protect her throne from Mary, Queen of Scots because Mary's encryption was broken revealing her plans to take the throne, thus influencing the course of British history. Who knows what would have happened if Mary had succeeded in gaining power.

In World War II, the story of breaking the German Enigma is a fascinating one. The contribution of the Poles and British to stopping the Nazis, in my opinion, made the difference in the outcome of the war. A number of people were left of history even though they invented techniques and methods (such as public-key cryptography) because they worked for government agencies that required secrecy. The Code Book helps to bring recognition to these people, some of whom will not know this because they passed away. Others missed out on the economic benefit that would have been available if they worked in the private sector. We all owe them much.

Singh does a masterful job telling the story through historical events as well as highlighting the developments in cryptology, marking the important breakthroughs for the code makers and the code breakers. It is easy to forget that at one time the Caesar cipher was considered secure.

One of my favorite detours in the book is a chapter on breaking languages and its relationship to code breaking. The are underlying similarities which make this chapter appropriate that are explained in the breaking of Egyptian hieroglyphics and Linear B. Each of them is as cool a story as breaking the Enigma.

The chapter on quantum cryptography, one of the few in crypto history books, provides a interesting look into our future. The struggle between code writers and code breakers is the dominant theme of the book through history. Now it appears that struggle will take an sharp turn into the Twilight Zone with the possibility of truly unbreakable crypto, although that is what people thought each time a new method was developed.

The book has a series of ten challenges at the end to test out your skills with a monetary reward if you can beat them all.

The Code Book is well written and well researched making for enjoyable reading. Some of the material is covered elsewhere and some is not, but the overall presentation stands on it own just fine. It is recommended as a book of history, as well as a book for learning about how various ciphers work and how they can be broken with clear, detailed explanations.