Programming

The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography

Format: Paperback
Author: Simon Singh
ReleaseDate: 29 August, 2000
Publisher: Anchor
Rating:

Accessible Summary of Codes, Etc.
His narration of the (frequently military) history surrounding some important events in the history of cryptography added considerable interest for me; there's just enough of it to add another dimension without there being so much that it detracts from the main story. Simon Singh has done an excellent job of narrating the history of codes and ciphers, covering material in quite a comprehensive manner, yet explaining it in a fashion that even readers who are not particularly gifted in mathematics will understand. His decision to include the decipherment of Egyptian hieroglyphics and Cretan Linear B script was a wise one, as well. As he notes, neither was an attempt to conceal the meanings, but the methods used are exactly parallel to many used in deciphering codes and ciphers.

Highly recommended.

Makes cryptography entertaining
It explains the idea behind several kinds of encryption strategies starting with Mary Queen of Scots and how her personal involvement in the plot against Queen Elizabeth I of England was exposed when her correspondence that was encrypted with simple monoalphabetic substitution was decyphered. This book is an excellent one that intertwines the history, strategy, and mathematics of those dedicated to encrypting messages and those dedicated to exposing the encryption strategy and thus the message.

This method was replaced with the polyalphabetic Vigenère square, which protected military and government dispatches for 250 years, until the Victorian polymath Charles Babbage, who believed that the cipher was flawed in some small way, set about the task of finding that flaw, and eventually did so.

Chapter 3 discusses how the invention of radio at the beginning of the 20th century enabled cryptanalysts to easily gather large amounts of intelligence, since anyone with an antenna could easily intercept enemy communications, thus driving the need for stronger encryption methods. This resulted in the "mechanisation of secrecy," the creation of machines to scramble messages beyond the manual abilities of human beings. This contributed to the public-key cryptography widely used today by businesses and governments.

The next chapter is about the Enigma machine, used by the Germans leading up to and during the Second World War, which performed a complex polyalphabetic substitution cipher. The book discusses how Alan Turing, a brilliant mathematician who devoted himself to the war effort, helped to crack the Enigma code machines used by the Germans. Turing and his colleagues' breakthroughs prevented U-boat attacks and ultimately shortened World War II, but because of the British intelligence community's policy of maintaining secrecy for its operations, his important work in this field was never recognized.

"Language Barrier" discusses how the American military used Navajo Indians as code talkers because of the unique characteristics of their language. It also discusses the Rosetta Stone and how it was used to decode a lost language by using two other known languages.

"Alice and Bob Go Public" discusses the solution to the so-called key-distribution problem. It talks about how James Ellis, employed by the UK Government Communications Headquarters, worked out how to achieve effective public key cryptography several decades before American academics published their solutions, and what those solutions were.

In "Pretty Good Privacy" Singh talks about what sort of line that law enforcement agencies should take pertaining to civil liberties. This leads up to the story of Pretty Good Privacy and Phil Zimmermann's battle with the government.

The final chapter is about quantum cryptography. The advantage this method has over traditional methods is that the exchange of information can be shown to be secure in a very strong sense, without making assumptions about the intractability of certain mathematical problems. Even when you assume the presence of hypothetical eavesdroppers with unlimited computing power, the laws of physics guarantee (probabilistically) that the secret key exchange will be secure, given a few other assumptions. I found Singh's explanation of this topic a bit more difficult to grasp than those in previous chapters.

I highly recommend this book as a starting point for anyone interested in the subject of cryptography. Even if you are not interested in going any further with this subject, it is an accessible and interesting read.
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Great
Singh performs a whirlwind tour of cyphers in "The Code Book". Mr. A good light introduction to crypto.