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

The need for efficient and secure communication has been part of the human experience for the entirety of recorded human history. Especially for those in power and charged with the governance of nations and armies—kings, queens, generals, etc.—communication that can be kept secret and safe is a perpetual necessity. This particular need is what drove the development of modes of communication that would be safe from prying eyes while being simultaneously intelligible to those to whom the message was addressed. As such, the development of codes and ciphers—“techniques for disguising a message so that only the intended recipient can read it” (10)—was a natural development.

The Code Book has two goals. The first goal is to describe and explain the evolutionary development of codes through the course of history up to the present day. As codes are cracked and ciphers are solved, they go through changes that attempt to make them stronger and more impregnable. This process allows codes to evolve over time, becoming increasingly complex as time goes on and the means of breaking them simultaneously increase. The second goal of the book is to prove that the subject matter, though of great importance in times past, is of even greater importance in the present day. While secret communication has always been important, today the use of encryption needs to protect identities, financial transactions, and much more.

In this light, many ethical questions arise, the most obvious of which is the dilemma of balancing between privacy and security. While cryptography would seem to be necessary to protect privacy, it would also seem to hinder the pursuit of nefarious deeds and persons. This tension is at the heart of much debate surrounding the implementation of encryption in the modern technological world.

In many ways, the world has been heading in this direction ever since the start of the 20th century thanks to the various wars fought all over the world. The First World War was called the “chemists’ war” due to the use of chemical warfare, while the Second World War has been called the “physicists’ war” on account of the development (and detonation) of the atom bomb. If there is a Third World War, it may well be “the mathematicians’ war” (13) because of the all-consuming ability of information (gleaned digitally and algorithmically) to change outcomes of events more rapidly than ever before.

In the course of the book, cryptography will be placed alongside other similar modes of indecipherable communication: codes, ciphers, and ancient languages. Though similar, they all have their own specific difficulties and characteristics. Codes are specific types of communication events that have been transposed in some way: “In a code, a word or phrase is replaced with a word, number or symbol” (13). Ciphers, on the other hand, break the communication down into even more discrete parts, acting “at a more fundamental level, by replacing letters rather than whole words” (14). The exploration of ancient languages gathers some of these characteristics together with the caveat that they were never meant to be indecipherable in the first place and yet have become so thanks to some accident of history.

While there will be many instances of quite technical language and terminology throughout the book, it will typically be very easy to tell what is being spoken about. In the course of the book, much of what has been previously secret or classified will be discussed and pored over, and so if there are mistakes or misleading information—or perhaps even outdated information—it will largely be impossible to tell. As the author observes, “The only people who are in a position to point out my errors are also those who are not at liberty to reveal them” (15).