The Code Book by Simon Singh

Spies, secrets, and codes.

Coding and decoding , or in Greek terminology, cryptography and cryptanalysis -- are perfect examples of direct and inverse problems. They share the basic features of both: the inverse problem is generally far more difficult to solve, and there may not be a unique answer.

The Code Book by Simon Singh, emerged from one section of the author’s earlier work,“Fermat’s Enigma”, chronicled the 350-year effort to find a proof of what was the most famous unsolved problem in mathematics, Fermat's last theorem. The Code Book leads readers on a journey through the history of coding, cryptography, and codebreaking. From primitive to high tech, Singh effectively crafts a narrative that turns cyphers into living, breathing beings that mutate from their humble beginnings as ancient hieroglyphics, into complex mathematical equations, that ultimately land on the shore of Internet surfing — communication by email. The incessant tug-of-war between code-makers and code-breakers kept my eyes darting from page to page as every seemingly unbreakable, gradually more complex code was peeled back to its essence and disposed of resourcefully.

Singh's approach is to make each of a series of historical incidents the frame for holding the reader's interest as he fills in technical details of successive coding systems. His exposition is especially effective at putting the reader in the code breaker's shoes, facing each new, apparently unbreakable code, until the discovery of a breakthrough idea uncovers a new form of vulnerability.

The book starts with an explanation of the differences between cryptography, steganography, ciphers, encryption, and decryption, before delving into the detailed techniques of various ciphers, including Monoalphabetic, Caesar shift, Vigenere, Pigpen, Playfair, EDLSs, and Morse Code. The author also explores the intriguing topic of deciphering ancient Egyptian and Greek texts, such as Hieroglyphics, Linear B, and Linear A. Move on to the next topic, Sign dives into the standardization of encryption and today's popular encryption mechanisms like DES and RSA, as well as the future of cryptography with quantum computing.

One of the most interesting parts of the book was the political and covert aspects of cryptography, particularly during times of war. Singh illustrates how codes and ciphers have been instrumental in shaping significant events throughout history, including their pivotal role in the outcome of World War II.

During World War II, the German military used the Enigma machine to encrypt their messages. However, the British mathematician Alan Turing and his team at Bletchley Park were able to crack the Enigma code, providing vital intelligence that helped the Allies win the war. Another example will be in the 16th century, Mary, Queen of Scots, used a cipher to communicate with her co-conspirators in a plot to assassinate Queen Elizabeth I of England. However, the cipher was ultimately cracked by the English cryptanalyst Thomas Phelippes, leading to Mary's arrest and execution. In the 19th century, the French used a cipher system known as the Great Cipher to protect their sensitive diplomatic messages. The system was so secure that it remained unbroken for over 200 years until a team of cryptanalysts led by Étienne Bazeries finally cracked it in 1893.

One of the notable strengths of "The Code Book" is how Singh deftly balances technical details with compelling storytelling. The author provides just the right amount of technical information to explain the underlying concepts without overwhelming the reader. If I had one complaint about this book would be the lack of depth when it comes to exploring the ethics and legal issues surrounding cryptography.

Overall the book is replete with fascinating puzzles and examples for readers to ponder, making it a stimulating and informative read for anyone interested in the history and science of cryptography. While it may not be a comprehensive guide to modern encryption methods, it provides an engaging and accessible introduction to the subject, and is a must-read for anyone interested in the fascinating world of codes and ciphers.