Codes and ciphers

THE CODE BOOK - The Secret History of Codes & Code-breaking: Simon Singh; Fourth Estate Ltd., 6, Salem Road, London W2 4BV. Received from the Research Press, Post Box 7208, First Floor, Arun House, 2/25, Ansari Road, New Delhi-110002. œ. 7.99.

ENCODING AND decoding of messages, both in times of war and peace have been in existence since the time humans began writing. And the story of codes and ciphers is the age old battle between code- makers and code-breakers. In this battle only the fittest could survive; and they did so by evolving improved codes all the time to fight the onslaught of the code-breakers. The author of the book under review has presented an interesting account of how ciphers and codes can be constructed and cracked. In doing so he has in the main, dealt with two aspects: on the one hand, he presents an evolution of a multitude of codes and ciphers over a time spanning centuries and, on the other has illustrated how, in today's world of information technology and digital computers, this subject has become all the more relevant.

In the opening chapter he narrates the cipher story of Mary Queen of Scots of the 16th century. The Protestant nobles rose against her, compelling her to abdicate. Her presence in England gave rise to countless plots and, after the Babington conspiracy in 1586 A.D., she was executed. Sir Francis Walsingham, Secretary of State to Queen Elizabeth I, who was a strong opponent of the Catholics, was very much involved in this episode, developing a complex system of espionage at home and abroad. The author gives an account of how Mary Queen of Scots was let down by the double crossing Gifford and found guilty of the charge of planning to assassinate Queen Elizabeth I. At the root of all this was a false sense of security generated by a weak cipher used by Mary Queen of Scots. Mary and Babington had relied upon this cipher to keep their plans secret which was easily cracked by her enemies. In the same year when Mary's cipher was cracked, the French mathematician, Vigenere, published his book on secret writing based on polyalphabetic encryption. A few decades later the cryptographers of Louis XIV invented what came to be known as the Great Cipher which could not be broken for another two centuries. When it was finally cracked it is supposed to have solved the mystery of the ``Man in the iron mask''.

Charles Babbage (1791-1871 A.D.), the British mathematician and computer scientist, was also interested in cryptology and made his contribution in cracking the Vigenere cipher. But since he never published his work, this did not come to light until the 20th century. The author also briefly mentions Sir Arthur Conan Doyle's The Adventures of the Dancing Men and Edgar Alan Poe's The Gold Bug where the direction to Captain Kidd's secret treasure trove is revealed. Then there is the story of Beale's Ciphers that relates to a 19th century cowboy who amassed a vast fortune left buried and now valued at $20 million. The Beale's ciphers are yet to be cracked.

With the invention of the radio by Marconi towards the end of the 19th century, the scenario underwent a drastic change. Anybody could break into a wireless communication and cryptographers had a new challenge on hand. The famous Zimmermann telegram sent to the German ambassador in Mexico outlining an encrypted proposal to draw the U.S. into the war finds mention in the book.

The Zimmermann telegram altered the course of history. Then there is that Holy Grail of cryptography known as the one-time pad, the only known form of encryption that is uncrackable. It relies on a random key that is the same length as the message and is never repeated. This one time pad, however, did not find favour with cryptographers due to some practical difficulties. The author tells the reader about the Enigma, an encryption machine invented by a German, Arthur Scherbius. Enigma was to become the most formidable system of encryption. During World War II Germans had a network of about 30,000 Enigmas with ironclad security. England set up its Government Code and Cyber School (GCCS) in Bletchley even as Hitler invaded Poland.

The author gives a detailed account of how Alan Turing, a cryptanalyst in GCCS, proceeded to work diligently and succeeded in cracking the Enigma. This was a decisive factor responsible for the Allied victory in World War II. Turing, in spite of his outstanding abilities as a code-breaker, never achieved any public recognition mainly because of his sexual preference (he was a homosexual); he was persecuted by his co- workers and, at the age of 42 he committed suicide. The author also gives an account of the code-talkers of the Navajo tribe, who were enlisted by the Americans to pass on intelligence in their language which made no sense to the enemy.

The author next discusses in some detail the archaeological attempts to decipher ancient writings like the Egyptian hieroglyphics, the earliest of them dating back to 3000 BC, a form of ornate writing that was in use until about 500 AD. The famous Rosetta Stone, inscribed around 196 B.C. in the demotic script that was less complex than hieroglyphics, was accidentally stumbled upon by Napolean's army in 1799. This priceless slab in black basalt, weighing about a tonne, was installed in the British Museum in 1802 where it is still attracting visitors. There is quite a lot in this book that makes a fascinating reading. Towards the end the author discusses the present digital age and the information explosion and how the digital technology can be very effectively used in the area of encryption and decryption. With the exchange of digital information becoming an integral part of our social and business intercourse, encryption has a leading role to play in protecting the confidentiality in business transactions and the privacy of the common citizen. The author has elaborated on various electronic encryption and decryption techniques and talks about the digital signature used to authenticate documents sent over cyberspace.

He also touches upon a sensitive but important aspect, viz. the debate put forward by civil rights leaders emphasising that privacy is a fundamental human right recognised by the Universal Declaration of Human Rights. In contrast, the law enforcing agencies fear that the Internet, coupled with cryptography, will help criminals to encrypt not only their communications but their plans and documents as well. While this debate goes on the Net surfer is free to download encrypting software like PGP (pretty good privacy) and feel assured that his/her e-mail communications are having a level of security that is beyond the combined efforts of all the existing codebreaking techniques.

In the last chapter he has presented some futuristic ideas that may enhance or destroy privacy in the 21st century, examining on the one hand, the possibility that the cryptanalyst may break all ciphers, while on the other hand, presenting a system of cryptographic methods that have the potential to guarantee absolute privacy.

When we have the new form of computer known as the quantum computer, that will make the present day super computers look like a broken down abacus, it can be expected to provide guaranteed secure communication for all. But how will law enforcing agencies regulate quantum cryptography so as to enrich the Information Age without protecting the criminals? Only time will provide an answer. There are some interesting appendices at the end of the book explaining certain encryption methods as well as a detailed write-up titled ``The Cipher Challenge: 10 Steps to œ10000'' that presents everyone an opportunity to put his/her cipher cracking skills to the test and win œ10000. A look at the pages that present this encrypted puzzle will leave the reader absolutely perplexed.

C. V. SUBRAMANIAM

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