The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography
New York: Random House, 1999, 432 pp.
The Code Book is about the mathematics and science of codes and ciphers throughout history. Singh specifically lists two purposes for this book. The first is to show the evolution of codes and ciphers, and the second is to demonstrate their relevance in today’s society. Throughout the eight chapters, he discusses the elements of complex ciphers and simplifies the mathematical details for a general audience. He enthusiastically presents stories surrounding ciphers such as who created them, who sought to break them, and if and how the codebreakers were successful. We, as student and instructor in a course entitled Networks for Cyber Operations, used this book as one of our texts in the Spring semester of 2016.
To illustrate his first point, Singh shares stories about well-known ciphers such as those involving Mary Queen of Scots, the Beale Papers, and the Enigma. He uses Mary Queen of Scots to show the evolution of secret writing and the development of cryptography. He discusses how secret writing evolved into steganography and cryptography, how cryptography developed into transposition and substitution, and lastly, how substitution evolved into codes and ciphers. Additionally, he discusses the story behind the Beale Papers to introduce how codemakers use keys to encrypt their messages. Sharing the story of the Enigma Machine in World War II, he shows the evolution from encryption by hand to encryption by machine. Singh also reveals how codebreakers accomplished their work to demonstrate that as long as codemakers develop new codes and ciphers, codebreakers will continue to break them.
This leads into Singh’s second purpose: to demonstrate the relevance of codes and ciphers into today’s society. Singh discusses the increasing value of encryption in the information age and the potential of quantum cryptography. His chapter on today’s information age where information is a “valuable commodity” (p. 372) – is our favorite. He speculates that one significant problem is that individuals do not encrypt their information enough, especially as it is transmitted over the Internet. Although encryption in internet systems has drastically improved since his book’s release in 1999, today’s citizens are still subject to devastating cyberattacks because of a lack of adequate encryption.
The Code Book contains several important lessons for today’s cyberspace citizens. Enciphering techniques are constantly developing and need to be incorporate into modern information systems. Over time, there is no guarantee that a cipher or code, which is safe one day is not vulnerable the next. Likewise, sometimes a code that may seem broken one day, can’t be broken the next because humans constantly improve and change enciphering machines. This means that codemakers and codebreakers must be ready to adapt. They must think in new ways and learn new ciphering and deciphering techniques as needs emerge. Another lesson is that every machine that humans have claimed to be “unbreakable” has been broken. This raises the question, can an unbreakable cipher actually exist? It is true that some ciphers are extremely difficult to break, and the quest for cryptanalysts to create codes and ciphers that are appropriately secure is based on the value of the information contained in the messages that will be encrypted.
The Codebook is valuable because readers can learn about the history of codes and ciphers. Some of the futuristic ideas that Singh discusses have progressed since his book; however, many of the encryption issues that he mentions still exist in today’s cyber-connected society. The Codebook is also valuable because it depicts the evolution of codes and ciphers as well as firmly establishing the relevance of encryption in today’s world.