This is the second book by Simon Singh, and he readily admits that he was surprised by the success of the first; 'Fermat's Last Theorem'. If you enjoyed that, then this will delight and entertain you, as well as lead you forward in an easy manner. There are some very complex ideas and processes encountered, yet each is tackled not as a whole, but as a series of small steps, explained in simple terms. It seems that the author subscribes to the notion that there is no such thing as a hard subject - the only hard part is the number of simple steps that are used, and the order they are combined, in order to reach the complex picture.
Singh states from the beginning that the book has two aims; to chart the evolution of codes, and to show that the study of codes and cryptology is as relevant for today as ever. Information always has had a high value, and there have been divers means employed throughout history to keep matters private where appropriate. The reasons for this secrecy are not always the same, but whether it is political, military, security or commercial, organisations and governments want to know that their information is safe, and at the same time strive to read similar matter from opponents. The history of codes and code breaking has been a struggle between the code makers, and the code breakers, with sometimes one and sometimes the other having the ascendancy. Sometimes intrigue and espionage have enabled a foothold to be gained to enable code breaking to continue.
The early use of codes and ciphers are explained well, and the author uses imaginative illustrations to convey his ideas. The chapters on modern developments, with private and public keys, for example, are brought to life with the example of mixing the colours of private paint stores. A mental picture is much better than mere words to describe the one-way functions that are used in encrypting and deciphering messages using public and private keys. It is also necessary to understand some of the early developments in code making and code breaking to grasp what happened at Bletchley Park, in the breaking of the Enigma codes during World War II. Singh admits to simplifying the Enigma story, but this does not detract from a particularly absorbing part of the book. There is also good list of books and web sites, for those wishing to gain more information. This applies to many of the code stories, whether this is from archaeology (the Rosetta Stone, or Linear B), or the actual use of encryption (the Zimmermann telegram, Pretty Good Privacy).
'The Code Book' was published prior to the events of September 11th 2001, but asks some pertinent questions on the nature of security. Just as code breaking and code making have been battling for many years, now that there are 'unbreakable codes' available, the debate has moved on to the need for security or the protection of individual freedoms. It is believed that the Data Encryption Standard (DES) was weakened to enable this to be broken by US government agencies. This book is not just a popular and populist history; it also raises questions that are relevant to us all. That is why the second of Singh's aims has been met. The first is achieved in a hugely entertaining read.
Incidentally, the cipher challenge is still an integral part of the book, although the prize is no longer available. It took 1 year and 1 month for the challenge to be successfully claimed, a tribute to the difficulty of the ten parts. If you have read the book, and have a few idle moments, perhaps you would like to try to crack the Beale ciphers and claim the huge cache of gold and silver that the documents describe. Oh, and when you have finished that, there is always the breakthrough that is waited for Linear A.
Peter Morgan, email@example.com