Friday, July 22, 2011

The Code Book

Author:      Simon Singh
Published:  1999
Publisher:   Fourth Estate Limited
Hardcover: 416 pages

The need for information security which is  widely recognized in this Internet Age is not a new need at all. It,though not as pervasive as today,  has existed for thousands of years and has a fascinating history of its own.

The high risk of secret and confidential messages sent by kings, queens and army generals falling into the  hand's of the enemies led  to the development of codes and ciphers. This heralded the birth of  Cryptography which is a method of disguising a message in a manner that only the intended recipient can read it. To counter Cryptography the unauthorized message interceptors worked on breaking the code. Thus evolved the science and art of codebreaking i.e. Cryptanalysis.

So the entire history of cryptography is the story of ongoing battle between Cryptographers (code makers) and Cryptanalysts (code breakers). And this story - right from the origin of ciphers in ancient Greece till the recent advances (till 1999) in Quantum Cryptography- is brilliantly narrated by Simon Singh in this book.

Singh mentions in the introduction to the book the two main objectives of his writing this book.
The first one is to chart the evolution of  codes. He describes how the battle between codemakers and code breakers involved diverse range of disciplines like mathematics, linguistics, information theory, quantum theory etc. and their associated technologies and inspired a series of remarkable scientific breakthroughs. He also enthralls us with " stories of political intrigue and tales of life and death to illustrate the key turning points in the evolution of codes", just to mention a few - the Babington Plot, the unbroken Beale Cipher, cracking of the Enigma code by  Alan Turing (of the well known Turing Test fame), decipherment of Egyptian hieroglyphics through Rosetta Stone.
The second objective of the author is to demonstrate how the subject of cryptography is as relevant today as it was before. Apart from providing one of  the best explanation I have ever come across of the prevalent encryption algorithms , standards and techniques  like DES, RSA, PGP, he explores the promising Quantum cryptography which can lead to unbreakable ciphers. He also discusses the debate between two schools of thought - one which lobbies for  restricting   the use of cryptography to ensure law enforcement and national security and the one which presses for its widespread use to protect the privacy of the individual.

This book also introduces us to the tireless cryptographers and cryptanalysts who had to remain anonymous  and never gained public recognition during their lifetimes. This was due to the politically or militarily sensitive nature of their contributions and inventions which could not be disclosed to public.
For example, by 1975, James Ellis, Clifford Cocks and Malcolm Williamson working for Britain's Government Communications Headquarters (GCHQ) had discovered all the fundamental aspects of public-key cryptography. Yet they all had to remain silent since their work was a classified information. They had to sit back and watch as Rivest, Shamir and Adleman the researchers in MIT rediscovered their discoveries over the next three years and became famous in cryptographic circles for their RSA algorithm.
Similarily during Second World War, the work of Max Newman and Tommy Flowers resulted in development of Colossus machine in Britain. Colossus was a precursor to the modern digital computer. Yet it was destroyed after the war and those who worked on it were forbidden to talk about it. This secrecy on the part of British Government meant that Eckert and Mauchly of the University of Pennsylvania got the credit for the invention of the first digital computer- ENIAC.

The technical concepts in this book are very lucidly explained and should no pose problems for a lay reader. Also an extensive list of further readings has been provided for the readers who seek more details. 

One of the most interesting books I have read this year. It has sparked an interest for Cryptography in me. Hence strongly recommend it as an introductory book on history and concepts of Cryptography and Cryptanalysis !

Useful Links:
Cryptography section of the author's website which has :

An Interesting Trivia from the Book:
Alan Turing (of the well known Turing Test fame) was conceived in the autumn of 1911 in India, where his father was a member of Indian civil service. His parents were determined that their child should be born in Britain, and returned to London, where Alan Turing was born on 23 June 1912 !