Cryptography is one of those subjects that are rarely written about, and books on its history are even rarer.
In The Code Book: The Secret History of Codes and Code-Breaking published in 1999, Simon Singh, the author, recounts events in the past which, had it not been for cryptologists and cryptanalysts, might’ve turned into a very different present in the world as we know it.
The story of secret writing reaches back into the accounts of Herodotus or the “father of history” and how the practice defined Greek history. The ancient Chinese and the Arabs also used the art form, first to cover the means of communication (steganography), which led to the development of cryptography, or the art of hiding the meaning of the message through encrypted symbols.
Singh’s book starts in the pivotal moment when Mary, Queen of Scots, is brought to trial for treason against her cousin, Elizabeth, Queen of England. Mary’s fate rests on letters she wrote in cipher that allegedly conceal a plot to kill the English queen. And unless the cipher is broken, she can’t be sentenced to death, which, for Elizabeth’s supporters, could mean defeat. We know how things turned out for that story (the descendents of Elizabeth still occupy the British throne), but Singh has a remarkable talent for storytelling, and Mary’s case is a riveting anecdote that opens out into the world of cryptography.
There are many other anecdotes that follow: how codes were made and successively broken, how governments had Black Chambers where classicists and theologians worked together to intercept and break coded messages. We learn of the brilliant motley of characters in Bletchley Park, the British Cypher intelligence team, who also laid the foundations for the birth of the modern computer, how machines were employed to make codes, how the world wars were won depending on who cracked whose codes first and managed to ambush the best-laid plans of the enemy.
There are stories of historical figures such as Charles Babbage, now recognized as the father of computer, who was also the first to break the Vigenère graph or Le Chiffre Indéchiffrable, but never laid claim to the fact; and Alan Turing, who formalized the concept of algorithm and created a machine, which is often regarded as the first general-purpose computer.
All these stories – a mixture of history, politics, archaeology, computer science, language, and mathematics – are brought together under cryptology.
The Code Book encompasses a remarkable spectrum of subjects but it’s not meant merely to be read. It’s made to make you think and interact, and try your hand at cryptology.
Singh guides the reader through symbols and messages, explaining how codes were made and broken. He starts with the very simplest of code-making methods (substitution of alphabets) and takes us to the very latest methods used today, and methods that are possible in theory but to accommodate which, machines have yet to be created.
Singh, a physicist and journalist, tells us of the quantum computer and how far the experiments have gone. But before we reach the world of gigantic prime numbers and unpredictable quantum theory, we’re given brief tours into the history of archaeology, and how cryptography has broadened our knowledge of ancient civilizations. If it hadn’t been for cryptographers, the Rosetta Stone would still be just another stone, and many archaeological findings would’ve been only ancient artifacts instead of the crucial keys they are regarded as today for the enormous amount of information they made available to us in the guise of symbols.
Singh also relates the story behind The Beale Papers, which have three cipher texts. The Papers is said to give information about buried treasure in Virginia worth millions of dollars today. Only one of the three cipher texts has been broken. Cryptanalysts have been poring over the others for many years.
The Code Book itself is a treasure map in some sense. At the end of the book is a Cipher Challenge, made up of 10 encrypted messages. Singh stated that the first person to solve the Challenge and break the cipher would win 10,000 Pound Sterling. A year and a month after the book was published, cryptanalysts succeeded in breaking the code and winning the money. However, the Challenge is still worth trying.
Also included in the book is the crossword puzzle published in the Daily Telegraph in 1942 to recruit cryptanalysts in the Government Code and Cypher School in Britain. Anyone who could solve the newspaper’s crossword within 12 minutes was invited to a challenge where his skills for solving the crossword were timed. When they succeeded, the six who had responded were recruited by British military intelligence as code breakers at Bletchley Park. You may not be recruited by British intelligence or win 10,000 pounds, but for the amateur cryptographer, The Code Book certainly unlocks a world shrouded in silence and mystery.