The Code Book: The Evolution of Secrecy from Mary, Queen of Scots to Quantum Cryptography - Hardcover

Singh, Simon

Hardcover

ISBN 10: 0385495315 ISBN 13: 9780385495318

Publisher: Doubleday, 1999

Synopsis

Codes have decided the fates of empires, countries, and monarchies throughout recorded history. Mary, Queen of Scots was put to death by her cousin, Queen Elizabeth, for the high crime of treason after spymaster Sir Francis Walsingham cracked the secret code she used to communicate with her conspirators. And thus the course of British history was altered by a few sheets of cryptic prose. This is just one link in humankind's evolutionary chain of secret communication, and just one of the fascinating incidents recounted in The Code Book, written by bestselling author Simon Singh.

Combining a superb storyteller's sense of drama and a scientist's appreciation for technical perfection, Singh traces the evolution of secret writing from ancient Greek military espionage to the frontiers of computer science. The result is an epic tale of human ingenuity, with examples that range from the poignant to the peculiar to the world-historical.

There is the case of the Beale ciphers, which involves Wild West escapades, a cowboy who amassed a vast fortune, a buried treasure worth $20 million, and a mysterious set of encrypted papers describing its whereabouts--papers that have baffled generations of cryptanalysts and captivated hundreds of treasure hunters.

A speedier end to a bloody war was the only reward that could be promised to the Allied code breakers of World Wars I and II, whose selfless contributions altered the course of history; but few of them lived to receive any credit for their top-secret accomplishments. Among the most moving of these stories is that of the World War II British code breaker Alan Turing, who gave up a brilliant career in mathematics to devote himself to the Allied cause, only to end his years punished by the state for his homosexuality, while his heroism was ignored. No less heroic were the Navajo code talkers, who volunteered without hesitation to risk their lives for the Allied forces in the Japanese theater, where they were routinely mistaken for the enemy.

Interspersed with these gripping stories are clear mathematical, linguistic, and technological demonstrations of codes, as well as illustrations of the remarkable personalities--many courageous, some villainous, and all obsessive--who wrote and broke them.

All roads lead to the present day, in which the possibility of a truly unbreakable code looms large. Singh explores this possibility, and the ramifications of our increasing need for privacy, even as it begins to chafe against the stated mission of the powerful and deeply secretive National Security Agency. Entertaining, compelling, and remarkably far-reaching, this is a book that will forever alter your view of history, what drives it, and how private that e-mail you just sent really is.

Included in the book is a worldwide Cipher Challenge--a $15,000 award will be given by the author to the first reader who cracks the code successfully. Progress toward the solution will be tracked on The Code Book website.

About this title

About the Author

Simon Singh received his Ph.D. in physics from the University of Cambridge. A former BBC producer, he directed an award-winning documentary film on Fermat's Last Theorem that aired on PBS's "Nova" series, and wrote the bestselling book Fermat's Enigma. He lives in London, England.

From the Back Cover

Praise for Fermat's Enigma by Simon Singh:
"Vividly recounted...I strongly recommend this book to anyone wishing
to catch a glimpse of what is one of the most important and
ill-understood, but oldest, cultural activities of humanity...an
excellent and very worthwhile account of one of the most dramatic and
moving events of the century."
--Roger Penrose, The New York Times Book Review

"How great a riddle was Fermat's 'last theorem'? The exploration of
space, the splitting of the atom, the discovery of DNA--unthinkable in
Fermat's time--all were achieved while his Pythagorean proof still
remained elusive...Though [Singh] may not ask us to bring too much
algebra to the table, he does expect us to appreciate a good detective
story."
--The Boston Sunday Globe

"It is hard to imagine a more informative or gripping account
of...this centuries-long drama of ingenious failures, crushed hopes,
fatal duels, and suicides." --The Wall Street Journal

"[Singh] writes with graceful knowledgeability of the esoteric and
esthetic appeal of mathematics through the ages, and especially of the
mystifying behavior of numbers." --The New York Times

"[Singh] has done an admirable job with an extremely difficult
subject. He has also done mathematics a great service by conveying the
passion and drama that have carried Fermat's Last Theorem aloft as the
most celebrated mathematics problem of the last four centuries."
--American Mathematical Society

"The amazing achievement of Singh's book is that it actually makes the
logic of the modern proof understandable to the nonspecialist...More
important, Singh shows why it is significant that this problem should
have been solved." --The Christian Science Monitor

Reviews

In an enthralling tour de force of popular explication, Singh, author of the bestselling Fermat's Enigma, explores the impact of cryptographyAthe creation and cracking of coded messagesAon history and society. Some of his examples are familiar, notably the Allies' decryption of the Nazis' Enigma machine during WWII; less well-known is the crucial role of Queen Elizabeth's code breakers in deciphering Mary, Queen of Scots' incriminating missives to her fellow conspirators plotting to assassinate Elizabeth, which led to Mary's beheading in 1587. Singh celebrates a group of unsung heroes of WWII, the Navajo "code talkers," Native American Marine radio operators who, using a coded version of their native language, played a vital role in defeating the Japanese in the Pacific. He also elucidates the intimate links between codes or ciphers and the development of the telegraph, radio, computers and the Internet. As he ranges from Julius Caesar's secret military writing to coded diplomatic messages in feuding Renaissance Italy city-states, from the decipherment of the Rosetta Stone to the ingenuity of modern security experts battling cyber-criminals and cyber-terrorists, Singh clarifies the techniques and tricks of code makers and code breakers alike. He lightens the sometimes technical load with photos, political cartoons, charts, code grids and reproductions of historic documents. He closes with a fascinating look at cryptanalysts' planned and futuristic tools, including the "one-time pad," a seemingly unbreakable form of encryption. In Singh's expert hands, cryptography decodes as an awe-inspiring and mind-expanding story of scientific breakthrough and high drama. Agent, Patrick Walsh. (Oct.) FYI: The book includes a "Cipher Challenge," offering a $15,000 reward to the first person to crack that code.
Copyright 1999 Reed Business Information, Inc.

The ancient battle between people who want to preserve secrets and people who want to discover them proceeds as a form of evolution. Codemakers devise a better means of encryption; codebreakers solve it, forcing the encoders to find another improvement. Singh, trained in physics but now an author of works on science, spins an absorbing tale of codemaking and codebreaking over the centuries. Does the simple monoalphabetic substitution cipher, which replaces each letter of a message with a letter from a cipher alphabet, no longer suffice? Replace it with a code using two or more cipher alphabets. When that no longer outwits the cryptanalysts, encode with a Vigenère square, in which a plaintext alphabet is followed by 26 cipher alphabets. And so on through one-time pad ciphers, cryptographic machines and public-key cryptography.

Singh explains them all deftly. Looking to the future, he sees "one idea in particular that might enable cryptanalysts to break all today's ciphers." It is the quantum computer. If it can be built, "it would be able to perform calculations with such enormous speed that it would make a modern supercomputer look like a broken abacus." Or perhaps the cryptographers will triumph with quantum cryptography. "If quantum cryptography systems can be engineered to operate over long distances, the evolution of ciphers will stop. The quest for privacy will have come to an end."

For millennia, secret writing was the domain of spies, diplomats, and generals; with the advent of the Internet, it has become the concern of the public and businesses. One cyber-libertarian responded with the freeware encryption program Pretty Good Privacy (PGP), and Singh similarly meets a sharpening public curiosity about how codes work. His first popular foray into a mathematical topic, Fermat's Last Theorem (1997), nicely balanced technical detail with vibrant storytelling, a quality happily present again here. Although the quantum-mechanical encryption with which Singh culminates his narrative is challengingly arcane to most except for the math spooks at the National Security Agency, Singh successfully conveys its essential principles, as he does those of all major ciphering schemes. Beginning with such simple ideas as monoalphabetic substitution, which can protect the communications of a boy's treehouse club but not much more, Singh underscores with stories how codemakers and codebreakers have battled each other throughout history. A tool called frequency analysis easily defeats the monoalphabetic cipher, and encryptors over time have added the Vigenere square, cipher disks, one-time pads, and public-key cryptography that underlies PGP. But each security strategy, Singh explains, contains some vulnerability that the clever code cracker can exploit, an opaque process the author splendidly illuminates. Instances of successful decipherment, as of Egyptian hieroglyphics or the German Enigma cipher system in World War II, combine with Singh's sketches of the mathematicians who have advanced the art of secrecy, from Julius Caesar to Alan Turing to contemporary mathematicians, resulting in a wonderfully understandable survey. Gilbert Taylor

Singh, Cambridge-educated physicist, has written a provocative study of code, the way in which humans hide the inherent meanings of messages by substituting words and or characters in a text. Author of the popular Fermat's Enigma, he broadly portrays the evolution of cryptography throughout the centuries. In essence, efforts of those wishing for secrecy and others who attempt to break it is a story of intrigue of the highest form. Employing a smooth narrative style, Singh tells of secrecy, fascinating events, and people, starting with Mary Queen of Scots and ending with recent attempts by quantum theorists to construct an unbreakable code. This is the history of technology at its best and serves as an excellent addition to David Kahn's mammoth work on cryptography, The Codebreakers (Scribner, 1996). Highly recommended for all public and academic libraries.
-ADayne Sherman, Southeastern Louisiana Univ., Hammond
Copyright 1999 Reed Business Information, Inc.

Excerpt. © Reprinted by permission. All rights reserved.

On the morning of Wednesday, 15 October 1586, Queen Mary entered the crowded courtroom at Fotheringhay Castle. Years of imprisonment and the onset of rheumatism had taken their toll, yet she remained dignified, composed and indisputably regal. Assisted by her physician, she made her way past the judges, officials and spectators, and approached the throne that stood halfway along the long, narrow chamber. Mary had assumed that the throne was a gesture of respect towards her, but she was mistaken. The throne symbolised the absent Queen Elizabeth, Mary's enemy and prosecutor. Mary was gently guided away from the throne and towards the opposite side of the room, to the defendant's seat, a crimson velvet chair.

Mary Queen of Scots was on trial for treason. She had been accused of plotting to assassinate Queen Elizabeth in order to take the English crown for herself. Sir Francis Walsingham, Elizabeth's Principal Secretary, had already arrested the other conspirators, extracted confessions, and executed them. Now he planned to prove that Mary was at the heart of the plot, and was therefore equally culpable and equally deserving of death.

Walsingham knew that before he could have Mary executed, he would have to convince Queen Elizabeth of her guilt. Although Elizabeth despised Mary, she had several reasons for being reluctant to see her put to death. First, Mary was a Scottish queen, and many questioned whether an English court had the authority to execute a foreign head of state. Second, executing Mary might establish an awkward precedent -- if the state is allowed to kill one queen, then perhaps rebels might have fewer reservations about killing another, namely Elizabeth. Third, Elizabeth and Mary were cousins, and their blood tie made Elizabeth all the more squeamish about ordering her execution. In short, Elizabeth would sanction Mary's execution only if Walsingham could prove beyond any hint of doubt that she had been part of the assassination plot.

The conspirators were a group of young English Catholic noblemen intent on removing Elizabeth, a Protestant, and replacing her with Mary, a fellow Catholic. It was apparent to the court that Mary was a figurehead for the conspirators, but it was not clear that she had actually given her blessing to the conspiracy. In fact, Mary had authorised the plot. The challenge for Walsingham was to demonstrate a palpable link between Mary and the plotters.

On the morning of her trial, Mary sat alone in the dock, dressed in sorrowful black velvet. In cases of treason, the accused was forbidden counsel and was not permitted to call witnesses. Mary was not even allowed secretaries to help her prepare her case. However, her plight was not hopeless because she had been careful to ensure that all her correspondence with the conspirators had been written in cipher. The cipher turned her words into a meaningless series of symbols, and Mary believed that even if Walsingham had captured the letters, then he could have no idea of the meaning of the words within them. If their contents were a mystery, then the letters could not be used as evidence against her. However, this all depended on the assumption that her cipher had not been broken.

Unfortunately for Mary, Walsingham was not merely Principal Secretary, he was also England's spymaster. He had intercepted Mary's letters to the plotters, and he knew exactly who might be capable of deciphering them. Thomas Phelippes was the nation's foremost expert on breaking codes, and for years he had been deciphering the messages of those who plotted against Queen Elizabeth, thereby providing the evidence needed to condemn them. If he could decipher the incriminating letters between Mary and the conspirators, then her death would be inevitable. On the other hand, if Mary's cipher was strong enough to conceal her secrets, then there was a chance that she might survive. Not for the first time, a life hung on the strength of a cipher.

The Evolution of Secret Writing

Some of the earliest accounts of secret writing date back to Herodotus, 'the father of history' according to the Roman philosopher and statesman Cicero. In The Histories, Herodotus chronicled the conflicts between Greece and Persia in the fifth century bc, which he viewed as a confrontation between freedom and slavery, between the independent Greek states and the oppressive Persians. According to Herodotus, it was the art of secret writing that saved Greece from being conquered by Xerxes, King of Kings, the despotic leader of the Persians.

The long-running feud between Greece and Persia reached a crisis soon after Xerxes began constructing a city at Persepolis, the new capital for his kingdom. Tributes and gifts arrived from all over the empire and neighbouring states, with the notable exceptions of Athens and Sparta. Determined to avenge this insolence, Xerxes began mobilising a force, declaring that 'we shall extend the empire of Persia such that its boundaries will be God's own sky, so the sun will not look down upon any land beyond the boundaries of what is our own'. He spent the next five years secretly assembling the greatest fighting force in history, and then, in 480 bc, he was ready to launch a surprise attack.

However, the Persian military build-up had been witnessed by Demaratus, a Greek who had been expelled from his homeland and who lived in the Persian city of Susa. Despite being exiled he still felt some loyalty to Greece, so he decided to send a message to warn the Spartans of Xerxes' invasion plan. The challenge was how to dispatch the message without it being intercepted by the Persian guards. Herodotus wrote:

As the danger of discovery was great, there was only one way in which he could contrive to get the message through: this was by scraping the wax off a pair of wooden folding tablets, writing on the wood underneath what Xerxes intended to do, and then covering the message over with wax again. In this way the tablets, being apparently blank, would cause no trouble with the guards along the road. When the message reached its destination, no one was able to guess the secret, until, as I understand, Cleomenes' daughter Gorgo, who was the wife of Leonides, divined and told the others that if they scraped the wax off, they would find something written on the wood underneath. This was done; the message was revealed and read, and afterwards passed on to the other Greeks.
As a result of this warning, the hitherto defenceless Greeks began to arm themselves. Profits from the state-owned silver mines, which were usually shared among the citizens, were instead diverted to the navy for the construction of two hundred warships.

Xerxes had lost the vital element of surprise and, on 23 September 480 bc, when the Persian fleet approached the Bay of Salamis near Athens, the Greeks were prepared. Although Xerxes believed he had trapped the Greek navy, the Greeks were deliberately enticing the Persian ships to enter the bay. The Greeks knew that their ships, smaller and fewer in number, would have been destroyed in the open sea, but they realised that within the confines of the bay they might outmanoeuvre the Persians. As the wind changed direction the Persians found themselves being blown into the bay, forced into an engagement on Greek terms. The Persian princess Artemisia became surrounded on three sides and attempted to head back out to sea, only to ram one of her own ships. Panic ensued, more Persian ships collided and the Greeks launched a full-blooded onslaught. Within a day, the formidable forces of Persia had been humbled.

Demaratus' strategy for secret communication relied on simply hiding the message. Herodotus also recounted another incident in which concealment was sufficient to secure the safe passage of a message. He chronicled the story of Histaiaeus, who wanted to encourage Aristagoras of Miletus to revolt against the Persian king. To convey his instructions securely, Histaiaeus shaved the head of his messenger, wrote the message on his scalp, and then waited for the hair to regrow. This was clearly a period of history that tolerated a certain lack of urgency. The messenger, apparently carrying nothing contentious, could travel without being harassed. Upon arriving at his destination he then shaved his head and pointed it at the intended recipient.

Secret communication achieved by hiding the existence of a message is known as steganography, derived from the Greek words steganos, meaning 'covered', and graphein, meaning 'to write'. In the two thousand years since Herodotus, various forms of steganography have been used throughout the world. For example, the ancient Chinese wrote messages on fine silk, which was then scrunched into a tiny ball and covered in wax. The messenger would then swallow the ball of wax. In the fifteenth century, the Italian scientist Giovanni Porta described how to conceal a message within a hard-boiled egg by making an ink from a mixture of one ounce of alum and a pint of vinegar, and then using it to write on the shell. The solution penetrates the porous shell, and leaves a message on the surface of the hardened egg albumen, which can be read only when the shell is removed. Steganography also includes the practice of writing in invisible ink. As far back as the first century ad, Pliny the Elder explained how the 'milk' of the thithymallus plant could be used as an invisible ink. Although transparent after drying, gentle heating chars the ink and turns it brown. Many organic fluids behave in a similar way, because they are rich in carbon and therefore char easily. Indeed, it is not unknown for modern spies who have run out of standard-issue invisible ink to improvise by using their own urine.

The longevity of steganography illustrates that it certainly offers a modicum of security, but it suffers from a fundamental weakness. If the messenger is searched and the message is discovered, then the contents of the secret communication are revealed at once. Interception of the message immediately compromises all security. A thorough guard might routinely search...

Edition details

• Publisher: Doubleday
• Publication date: 1999
• ISBN 10: 0385495315
• ISBN 13: 9780385495318
• Binding: Hardcover
• Language: English
• Edition number: 1
• Number of pages: 416