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Crypto

Secrecy and Privacy in the New Code War

Stephen Levy
Reviewed for the Sunday Telegraph

At the start of “Crypto”, Stephen Levy’s enthralling account of modern cryptography, the author makes the following devastating observation: “It may feel like we’re performing an intimate act when, sequestered in our rooms and cubicles, we casually use our cell phones and computers to transmit our thoughts, confidences, business plans, and even our money. But clever eavesdroppers, and sometimes not-so-clever ones, can hear it all. We think we’re whispering, but we’re really broadcasting.”

“Crypto” is the story of the technological developments that can potentially protect out privacy, enable e-commerce and, in short, provide the locks and keys of the Information Age. Prior to the 1970s, research into codes and codebreaking was hidden away in shadowy government laboratories, but as encryption has become a matter of economic necessity it has gradually emerged into the daylight. Levy, a highly respected technology journalist, has painstakingly researched the breakthroughs of the last thirty years, describing how a matrix of mavericks broke the government monopoly on cryptography.

In particular, the mavericks overcame a problem that had seemed so formidable that for two thousand years everyone had assumed that it was insurmountable. Essentially, if I want to send you an E-mail, but I am concerned that there is an eavesdropper, then I will encrypt my message according to some recipe. In order for you to decipher the E-mail, you need to know the recipe so that you can reverse it, but obviously the recipe has to be kept secret from the eavesdropper. Hence, the problem is, how do I get the recipe to you securely, when I know that there is an eavesdropper on the line?

For centuries, a sender and receiver would often rely on a trusted third party to courier the recipe between the two of them, but even this jeopardises their privacy. As one security expert put it, it is difficult for two people to have intimacy when someone else is in the bed. Intuitively, there seems to be no way for two people who have never met to establish a secure communication channel without the help of a third party. Nevertheless, mathematics obliges us with a solution, one that was uncovered step by step by half a dozen quirky Americans. Levy paints each of the cryptographers in loving detail, establishing them as mighty heroes in the battle for privacy.

The solution is known as public key cryptography. Unfortunately, there is not enough space in this review to outline what must be the greatest breakthrough in the history of cryptography, but suffice to say that I still vividly remember the afternoon when I first read about it some seven years ago. It is a concept of such audacity and elegance that, even today, the mere thought of it makes me tingle.

The invention of public key cryptography ignited a struggle between civil libertarians and law enforcers. Modern cryptography is so strong that any two people in world can download free crypto-software and send each other an encrypted email that cannot be deciphered by the combined forces of all the world’s secret services. Some view this as an opportunity to establish a golden age of privacy. However, critics of freely available strong cryptography point out that it would allow criminals and terrorists to evade police wiretaps.

Levy examines the political issues surrounding encryption and outlines the story so far. What is becoming clear is that the civil libertarians are currently winning the argument thanks to the support of the e-commerce lobby, which needs cryptography in order to conduct secure transactions. However, this is an ongoing debate, and one which we all need to be aware of, because our privacy and security are at stake. “Crypto” is an excellent primer for those interested in both the politics and science of cryptography and should be required reading for anybody interested in what will be one of the most influential technologies of the next decade.