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Crypto Q&A
Over the years, I have
been interviewed several times by various journalists. Below
is a compilation of some of the questions that I have been
asked about The Code Book and cryptography in general,
and my answers to those questions.
Secrets, mysteries,
puzzles: what makes them so appealing to almost
everyone?
Cryptography is the science of
secrecy. It is about the development of techniques that allow
us to protect our secrets, and we all have secrets. Ever since
people began to write, I imagine that people have invented
methods of encrypting those texts that contained illicit
affairs, military plans or recipes for alchemy. It is very
natural for everybody to want to protect their secrets, and
similarly we all want to find out the secrets of others, which
is where code breaking becomes relevant.
So you can see that cryptography is
a subject that should be of interest to many people,
especially because we now live in the Information Age, and our
secrets can be transmitted in so many ways – email, cell
phone, etc. – and all these channels need to be
protected.
How did you get the idea
for The Code Book?
My first book, Fermat’s
Last Theorem, was the history of a notorious mathematical
problem, and it included a short section on how mathematicians
use computers, and how computer development was driven by code
breaking in the Second World War. This brief encounter with
code breaking fired my imagination and I thought about writing
a history of code breaking going back 2,000 years and coming
up to the present Information Age.
I once heard how a biographer took
a minor character from his last book and turned him or her
into the main subject of his next biography. This is
effectively what happened in my case – the minor character of
cryptography in my first book became the major figure in my
second book.
Did this accidental
interest in cryptography pay off?
There were
four main reasons why cryptography is an ideal topic for a
book. First, the science is fascinating. The continual battle
between codemakers and codebreakers is full of brilliant
discoveries, which are elegant, ingenious and often completely
counterintuitive. Second, this is a science with a history
that goes back over 2,500 years. When explaining scientific
ideas, it really helps to have a history. As a writer and
populariser, it means that I can begin with earliest ideas,
which are relatively easy to explain, and then gradually
develop towards more sophisticated concepts. Third, secret
codes are at the centre of some wonderful stories, including
the execution of Mary Queen of Scots and the pivotal Zimmermann
Telegram in the First World War. Once again, from a writer’s
point of view, it was great to have such enthralling stories to
rely on. They illustrate the significance of secret codes,
they are gripping, and they provide a variation in pace
against the more purely scientific passages. Fourth, and
finally, secret codes are more relevant today than ever
before. For the first two-thirds of the book the reader learns
some great science and reads some great history, but in the
final third there should be the realisation that codes are having a very real impact as we enter the 21st century and
the Information Age. It is said that codes will provide
the locks and keys of the Information Age. You can’t send
personal e-mails without using cryptography to guarantee
privacy and you can’t have e-commerce without using
cryptography to secure your credit card details, and so
on.
What is your favourite
chapter or passage in The Code Book and
why?
My favourite story concerns the secret
discovery of the most important form of encryption of the
twentieth century, one that has transformed security in the
Information Age. The code breakers worked behind the closed
doors of a British Government research centre, so their work
was immediately classified and they received no credit for
their work. Their idea was subsequently re-invented in
America, but the British code breakers continued to receive no
credit. After 25 years of secrecy, whilst I was writing the
book, the British Government went public.
I am particularly fond of this
story because I feel privileged to be the first to write about
it at length. Also, the theme of the anonymous code breaker
recurs throughout the book. Code breakers, by dint of what
they do, rarely get the credit they deserve. The science of
secrecy is a secret science.
Which parts of The Code
Book did you enjoy researching the most?
For me the most fascinating aspect
of writing The Code Book was learning about each new code, and
thinking that it seemed unbreakable. Then after a bit more
research I realised how each code could be broken. The real
buzz was that moment when I discovered the weakness in each
code, when I suddenly realised out to unravel a particular
code.
Which chapter or passage of
The Code Book was hardest to write and
why?
The breaking of the German Enigma cipher
used in the Second World War was an extraordinary difficult
chapter to write. The story is remarkable, but unless a
science writer can also explain the science then there is a
certain emptiness. I struggled with the subject for several
months, and I think that I have succeeded in providing a clear
explanation. I worked closely with an illustrator who was able
to draw some elucidating diagrams, which I think will help
readers to understand how the Enigma works.
And I have now created a cryptography
CD-ROM which animates the Enigma, and this really
makes its internal workings crystal clear. There is even an
Enigma emulator so that you can encrypt your own
messages.
What was the challenge for
you in writing about the history of code breaking?
The main challenge was to decide
which stories and which scientific breakthroughs to select. I
wanted to create a digestible and accessible book, yet this is
a subject that spans 4,000 years and appears in every
continent. So I had to decide which stories were most
important, which ones linked best with each other, and which
were most exciting and interesting. For example, the Second
World War involved numerous ciphers, but I concentrated on the
making and breaking of the Enigma cipher, because this changed
the course of the war and it represented an enormous leap
forward for code makers until it was cracked ... at which
point it represented an enormous breakthrough for code
breakers.
Does the beauty of
mathematics lie beneath codes and code breaking?
Much of cryptography can be seen mathematically, but
this is a subject that also involves linguistics, computer
science and physics. The latest encryption system is called
quantum cryptography. Many people see this as a book that is
driven by mathematics, but I think that their view is
jaundiced by the subject matter of my first book, Fermat’s
Last Theorem. I think The Code Book contains a significant
amount of mathematics, but it would be wrong to ignore all the
other elements.
Have you now become a
master code breaker?
No.
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