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Encryption Books Media Security Book Reviews

The Code Book 47

Ellen Knowlton Wilson brings us this review of a book which has succeeded in presenting one of the important concepts of modern life -- cryptography -- by grounding it in its historical roots as well as its modern applications, including ones not yet implemented. (Read more.)

The Code Book: the Evolution of Secrecy from Mary, Queen of Sco
author Simon Singh
pages 402
publisher Doubleday
rating 8/10
reviewer Ellen Knowlton Wilson
ISBN 0-385-49531-5
summary Singh chronicles the development of codes and ciphers as well as their roles in human events, and discusses the relevance of cryptography in the modern age.


In The Code Book: the Evolution of Secrecy from Mary, Queen of Scots to Quantum Cryptography, Simon Singh begins with the courtroom drama of the trial of Mary, Queen of Scots, and ends discussing current debate over the export of strong cryptography tools. In between, he touches on the identity of the Man in the Iron Mask, buried treasure, the Enigma machine, Navajo code-talkers and quantum money, in a manner accessible to laypeople.

Singh approaches the story of cryptography from the perspective of both scientist and science writer. He received his doctorate in physics from Cambridge and produced a documentary about Fermat's Last Theorem which aired on both the BBC and PBS. He is also the author of Fermat's Enigma, which tells the story of Fermat's Last Theorem. Singh's background has prepared him well for this subject; he has the scientist's eye for detail and the writer's ability to communicate concepts in a non-patronizing manner. "Turning to purists," he writes in the introduction, "I should apologise for the title of this book. The Code Book is about more than just codes... Ciphers play an integral role in cryptography, and so this book should really have been called The Code and Cipher Book. I have, however, forsaken accuracy for snappiness."

Indeed, this book is not intended for the diehard cryptography buff, but rather for the general reader. Should the reader become captivated by the subject, Singh has included a section of suggested further readings. The book also contains a contest for $15,000 -- The Cipher Challenge (

Singh states in his introduction that the objectives of this book as twofold: first, to chart the evolution of codes and chronicle their impact on history; and second, to demonstrate the importance of cryptography in the modern age. Singh clearly succeeds with his first objective, but I found the case for the second to be slightly weaker.

The types of codes and ciphers are illustrated with stories of historical intrigue, such as the treason trial of Mary, Queen of Scots, who was executed when the cipher alphabet and code words used by her co-conspirators was cracked, revealing her involvement in a plot unfamiliar to most modern readers. The development of frequency analysis and polyalphabetic substitution ciphers is interwoven with the story of the buried treasure in the American west. The mechanization of codes and ciphers is covered in the sections about the first and second World Wars, and the relation of language and cryptography is illustrated by the use of Navajo code-talkers during the Pacific campaign of World War II. Concepts of cryptography are presented in an accessible and enjoyable manner throughout the book, although readers already familiar with the subject may not gain any new knowledge.

The final three chapters of the book cover public-key encryption and quantum cryptography. I found the explanation of the concepts behind PGP to be clear, and was fascinated by the brief explanation of the legal struggles surrounding encryption. Singh makes some good points about the importance of privacy in the current age, but does not delve too far into the subject. Admittedly, the question of information ownership is such a large one that it merits its own book. The final chapter covers quantum cryptography, which is illustrated by the idea of quantum money. Quantum money would contain polarized photons, known only to the bank, rendering counterfeiting impossible. While still purely theoretical, the idea is fascinating, and indicates the changes sure to evolve as technology changes.


The Code Book is an enjoyable and readable introduction to codes and ciphers for the layperson. Examples of the principles of cryptography are illustrated with examples from history, showcasing their importance of the history, and Singh attempts to make the case for the increasing importance of privacy as technology develops.

Purchase this book at ThinkGeek.

Table of contents:

  • Introduction
    1. The Cipher of Mary Queen of Scots
    2. Le Chiffre Indchiffrable
    3. The Mechanism of Secrecy
    4. Cracking the Enigma
    5. The Language Barrier
    6. Alice and Bob Go Public
    7. Pretty Good Privacy
    8. A Quantum Leap into the Future
  • The Cipher Challenge
  • Appendices
  • Glossary
  • Acknowledgements
  • Further Reading
  • Picture Credits
  • Index
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The Code Book

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  • 11.Can you imagine... a beowulf cluster of these? (oh uh, that Bateman guy's script is at it again!)

    We already have beowulf clusters of these things, they are called libararies.
    Lets just hope the Us Government doesn't decide that they are too powerful for public use and ban them..

  • Have to agree with other posters and the reviewer. This is a great book and an easy read / primer for crypto.

    The stuff on the Navajo Code Talkers was fascinating. I also really enjoyed his digression into the decipherment of Linear B...not strictly cryptography of course, but a fascinating case nonetheless.

    Another interesting tidbit was the revelation that the British has in fact come up with the idea of asymmetric ciphers and the RSA scheme a few years ahead of the researchers in the US...but were unable to publish their findings. The book is littered with such stories of British discoveries that had to be kept secret for years.....

    I say go get this book! You will not be disappointed.
  • Printed books generally do not have a problem with export from the US, finding protection under freedom of the press.

    It is only digital media that has had a problem, since the argument is that source code on disk is a tool, not an expressive essay. Apparently the assumption is that OCR software doesn't exist outside the US either :)

    Hence Applied Cryptography with detailed descriptions of strong algorithms can be exported by US booksellers, since there is no companion CD with it. The CD is sold only directly from the author (in MN), and only to US and Canadian buyers with check or money order drawn from a US bank. The CD is restricted from export, but the book is not. See for more detail.

    It is a strange country we live in where what format a book is in has great impact on where you can sell it.
  • an oldish article in Scientific American mentioned that a code Bacon used was one of the first uses of a binary numbering system -- it involved encoding a message using two slightly different fonts, distinguishable to those in the know, hidden in a open text letter. Every 5 characters in the open text would be one of two fonts (a or b, say), like "aabab (5-e) baaba (18-r) " etc.
  • I thought that the digression into the breaking of Linear B was a fascinating comparison to the efforts of codebreakers. The point that he made was that the techniques are >remarkably the same -- a code is like a language (in the information theory/machine automata sense), and in this case you need to use BOTH mathematics AND a knowledge of the people communicating to successfully break the code. I actually went out and bought "The Decipherment of Linear B" by John Chadwick after reading "The Code Book". When I read it, maybe I'll post a review to Slashdot!

    I do agree with your point about the "unbreakable" nature of Quantum Crypto. If there is any historical lesson to be learned here, it's that cryptography is a neverending arms race between the maker and the breaker. It just gets more interesting and has higher stakes as it goes on!
  • The Slashdot Jon Katz review [], another slashdot review [] by Allen Knowleton Wilson, and you can buy [] the book at ThinkGeek [].
  • .. in its selection, when its reviewed at Slashdot. Why else is this being reviewed again?

    In other words, it's just another ThinkGeek marketing plug.

  • I remember laughing out loud several times on the page where Singh describes the origins of the internet. I think he managed to cram most of the common misconceptions into a single paragraph at one point. But besides that, it is good light reading on the history of cryptography.
  • as mentioned this book is for the masses who want to learn about cryptography, but who couldn't factor 20, much less trying to pull prime factors out of some huge number. (see, I'm not even sure if thats how it works, but since I read the book I can now spout stuff like this out and pretend I know what I'm talking about!)

    The stories are all interesting, but I think what will interest /.ers is the discussion of PGP, and finally quantum cryptography. I also like the fact that Mr. Singh included a disclaimer at the beginning of the book that essentially says, 'all current technology I write about may have already been made obsolete by discoveries and applications already use by gevernments' - and then goes on to make a compelling case as to why this must certainly be true! All in all a good read.

  • by segmond ( 34052 )
    I just finished reading this book at 5am last night or this morning whichever way you look at it, and it is a great read. The last section on quantum psyhics application to quantum money, quantum computing and cryptography is great. I am going to restart the book over again. :-) It is the best read I have touched in a long time. I recommend it for anyone, One of the greatest things about cryptography is that it is very easy to understand, it can be broken down into very simple examples. The reason for this is that cryptography relies on number theory which is also very easy to understand "basics", it doesn't require algebra or calculus, just basic mathematics.

  • by AndyRae ( 39251 ) on Wednesday April 19, 2000 @02:51AM (#1124096)
    You can find the first review of this book here:

  • If not, why?

    Anyhow, one of the tenets of that book is that very good crypto will allow online virtual banking that no government will be able to trace.

    Kind of like an offshore bank, but quicker and easier to implement.

    The first geek/bankers to do this stand to become very rich.

    Income tax may disappear, being replaced with real estate taxes, etc. Society may change drastically.

    Get ready,

  • Yeah, but cryptography is *nothing like* as important as these things.

    I must disagree. To start with, cryptography is the rock upon which our banking and currency systems rest. If you use an ATM, or get your paychecks directly deposited, you've directly relied on cryptography. Even you keep your money in a mattress, the whole reserve banking system (upon which, for good or ill, the economy is based) needs it to function. Every day between one and two trillion dollars worth of interbank transfers [] are processed by Fedwire and the Clearing House Interbank Payment System; all these transations use cryptography.

    And cryptography is essential for modern military operations. Whether you're a hawk or a dove, you can't help but admit that military operation have an important impact on the lives of people around the globe, and that impact would (for good or ill) be much lessened in the absence of secure communication. Cryptography is also important in the diplomacy that holds tensions short of a state of war - the old "Red Telephone" line between Moscow and Washington was protected with, IIRC, a one time pad.

    Cryptography is used by people around the globe working for human rights; groups like Human Rights Watch and Amnesty International [] use cryptography to secure their communication.

    So, if you want to engage in commerce, protect or attack a nation, or are concerned about human rights, cryptography is fundamental. There are good reasons why it gives certain government agencies extreme heartburn to think of cryptography in the hands of the rest of us...

  • How can you say that when even now I'm sure that more than 90% of of the "modern world" has no inclination of what Cryptograhy is?
    More than 90% of the "modern world" has no knowledge or understanding of the Otto cycle, Maxwell's equations, or the Von Neumann architecture, either. Yet they keep relying on cars, radios, and computers on an everyday basis.
  • I enjoyed this book, and recommended it to a number of others. Perhaps because of familiarity with the subject matter, I found the chapters on modern cryptography like PGP and quantum cryptography less interesting than the classical forms.

    I took the time to solve six out of the ten contest codes. One more is about half solved. The two fun ones were cracking the 3-rotor Enigma machine (done by a hill-climbing search) and cracking a Playfair cipher by simulated annealing.

    Anyway, highly recommended.

  • Continuing with []:

    Yes, I saw the acknowledgement on the bottom of the page myself (about April 10), but supposedly this pertains to whomever can identify the source of the ciphertext, as opposed to deciphering it.


  • by Rocky ( 56404 ) on Wednesday April 19, 2000 @02:52AM (#1124102)
    I don't mean to bitch, but this review is a bit late for anyone who wasn't aware of the book and wanted to participate in the contest.

    According to the leader board, 8 out of 10 of the codes have already been broken, so get going if you wanted to participate in the last two!

    On an unrelated note, was anybody able to break the code on []?
    It has been taken down.

  • by revision1_1 ( 69575 ) on Wednesday April 19, 2000 @03:07AM (#1124103) Homepage
    I've read Kahn's _Codebreakers_ and Schneier's _Applied Cryptography_ and thought I'd pretty much covered the popular offerings on the subject, but picked up Singh's book based on an NPR interview I heard with him.

    It was great. I even got my (non-crypto-geek) wife to read it, and she thoroughly enjoyed it. It's a little lighter on theory, but richer in descriptive narrative. If you've read Kahn, you'll find many of the same episodes related in The Code Book, but Singh does a better job of describing some of the historical contexts (specifically, the activities of Queen Elizabeth and Sir Francis Walsingham).

    I was also glad to read some decent coverage of the much-under-appreciated Navajo Code Talkers of WWII, which barely rates a paragraph in Kahn. (By the way, The History Channel just ran an entire hour on the Code Talkers on their "Histories Mysteries" series - highly recommended)

    I liked The Code Book so much, I went back and picked up his earlier book, _Fermat's Enigma_ and was enthralled by the 350 year quest to solve the Theorem.

    Buy and enjoy. It deserves a place on the bookshelf next to Kahn and Schneier.

  • My wife bought this book for me for Christmas because I had enjoyed
    Fermat's Enigma (also by Simon Singh) so much. On Christmas Eve the book
    was presented to me. 48hrs later, I had read it through.

    If it hadn't been for familial obligations, I would likely have devoured
    it whole, at one sitting. Damn, DAMN good book.
  • Why start with Mary Queen of Scots?

    Because she's a great example of the dangers of poor cryptography. If using a 40-bit browser were likely to get you beheaded, you'd be more concerned about the quality of your crypto, wouldn't you?

  • I disagree with you:

    Even if you try an avoid the Internet, and never plan to do business on it, if you want your private information kept private then you need to be concerned with encryption.

    More and more states are keeping tons of information about you accessible to a hacker on some server somewhere - and if the info is kept encrypted it adds a little bit of safety (now if they don't have a trusted 3rd party and they keep their secret decryption key on the same computer as the data, well, I don't consider that to be a good use of encryption).

    Do you have a driver's license? Is your state dumb enough to use your SSN as your drivers license number (several do)? Register a gun? Get a speeding ticket? Want everyone to know everything?

    Crypto isn't just for political speech (you decide if your society is free or not) and dissident movements anymore.

    If you trust your work to keep your information secure, have you ever taken the time to think how secure?

    You should always remember Satires, VI, line 347
    Juvenal, C. 100 C.E.
    Sed quis custodiet ipsos custodes?
    (translated: Who will guard the guards?)

    You need to take things into your own hands sometimes, just stepping away from the computer won't make it all go away.
  • Actually, I just got back from a presentation on the importance of encryption to find your posting and I think I'm still rattling quotes from the speech.

    Nice ability to count there, and you do bring up an interesting other point I was talking about - I live in PA and there is a growing amount of Amish who take credit cards for various businesses they have, so even the Amish should think about how securely they send info or their customers could have their information stolen.
  • by LocalYokel ( 85558 ) on Wednesday April 19, 2000 @03:30AM (#1124108) Homepage Journal
    Did this book have to be written overseas and imported to the U.S, or is it simply illegal to export this book outside the U.S.?

  • He did, and the book goes as far back as that (and then some). Singh just uses the Trial of Mary Queen of Scots as a dramatic point in history where a life was at risk if a code could be broken (and it's a good hook to get you interested in the book). I also liked the chapter on the 'decryption' of the hyroglyphics and other lost languages.
  • by zpengo ( 99887 )
    Why is cryptography such an important subject? It seems to me that it's one of those "It's the principle of the thing!" ideas. What is the average geek actually doing with this powerful cryptography that we're all fighting for, except writing mash notes to his girlfriend, downloading video game demos, and buying penguin mints from ThinkGeek?

    Online transactions can be encrypted all day long, and still be compromised by some 1337 srk1p7 k1dd13 who makes his way into a poorly secured database server. We need more awareness of the perils of e-commerce (on the side of those offering it), rather than stronger cryptography. Demand more secure online stores, not codes that take h@x0rz an extra day to crack.

    (If you disagree, reply instead of modding me down).

  • The book really goes fast, thanks to all the little stories that accompany the technical things. The little adventures that it presents cryptography as being are rather engaging, at least as much so as the actual concepts and ideas the book expresses. As my first real introduction into cryptography, I enjoyed it, and since reading it have felt compelled to research more.

  • This is perhaps one of the best book reviews I've read on Slashdot.

    Good work!

  • So is source code - protected by first amendment - even crypto.
  • Not as good as his 'Fermat's Last Theorem'.
  • This sounds like a book worth getting - I keep a copy of Applied Cryptography on my desk, but find that I frequently have to hunt down my coworkers (who borrow it for "light reading").

    Thank you, /. [], for providing us with Hemos' review.
    Information wants to be free

  • Last I checked on the site, perhaps two weeks ago, it was up and he was saying congrats to a fellow that solved it - don't recall who he was or even where from. Perhaps that is why it is gone - interestingly enough, if you go to [] - you will see a similar, yet slightly different page.
  • A long time ago (soon after this book was published), I read a review of this book in the Nwe York Times. Having just read another book detailing the British cryptography efforts during WWII. However, this was more of a historical narrative from one of the insiders detailing how the author (whose name I forget) worked in Bletchley (sp?) Park. Anyways, I decided to also read this book, and I found it to be very informative. The section on Linear B was an showed an amazing feat of linguistic and cryptographic genius. The example of RSA encryption was very interesting, especaially when he gave some twelve digit or so numbers and said that it would take a few hours with a calculator to factor. Obviously, the TI-89 wasn't around back then. The increase in calculating power (just from the old handhelds to something as powerful as the TI-89) gives us a great hope for the future of cryptography. PGP now! PGP forever! :)
  • Why start with Mary Queen of Scots?

    I'm sure Julias Caesar used a simple substitution code based on a->d, b->e etc.
  • The point about quantum cypto being unbreakable is this: current (non-quant) methods are falible because of their very nature. Large-number factoring, for example, is tedious, with no shortcuts (unless the film 'Sneakers' is correct ;-). But that's just a pragmatic issue. In principle it could be cracked (given a few millenia).

    Quantum crypto, on the other hand, uses nature itself to help privacy. Listening in on my PGP email is simply impractical (and would be very dull - believe me). But to listen in on a quantum conversation without being detected would require breaking physical laws.

    The worry, of course, is that quantum mechanics isn't the whole truth. But that is another story.

  • How can you say that when even now I'm sure that more than 90% of of the "modern world" has no inclination of what Cryptograhy is?

    Sure, they want their banking information to be secure - but beyond that they don't have direct exposure to it on an everyday basis.
  • Yeah, but cryptography is *nothing like* as important as these things. You could apply this argument to almost any piece of technology which just happened to be ubiquitous. The frame buffer. The keyboard and mouse. The infrared remote control.

    Cryptography is a means to encode data to make it difficult for other people to decode. The Von Neumann architecture enabled the information revolution. You can't compare the two! You might as well say that "call waiting" is one of the most important concepts of modern life, and compare it to the invention of the telephone.

    Actually, I think GTE do this already

    (Ooh, by the way, it's nice to see impartial moderators at work. At least I know I can raise my karma by just agreeing with everything the editors say.)

  • - I keep a copy of Applied Cryptography on my desk, but find that I frequently have to hunt down my coworkers (who borrow it for "light reading").

    Now there's a book I enjoyed reading. Applied Cryptology was much better then the Code book IMHO. I'm thinking about buying Applied Cryptology... During college I guess I'm being spoiled by spending my time here in Penn State's Computer Lab...

    Maybe I should learn something important, like grammar while I'm here. :)

  • I took this book out of the Penn State Library a week or so ago. I didn't really get into it much however. The first two chapters were very boring in my opinion...The Mechanism of Secrecy and Cracking the Enigma were some of the more interesting things I remember skimming through.

    I think a very strong interest in crypto is neccessary to really enjoy this book... I'm not big into crypto but I do think it's an intersting subject.

    Anyone interested in crypto I'd say buy or borrow this book and give it a try yourself. It's not bad...

  • Actually, Quantum Money is no more secure than current money because of one simple fact: counterfeiters don't have to fool the banks, they only have to fool the people they're handing the fake money to.

    The problem with checking quantum money (this is explained in the book) is that by checking it you destroy the value. (Subject to Heisenberg's uncertainty principle, etc.) The only good thing about quantum money [] (IMHO) is that quantum cryptography evolved from it.


  • Having just finished this book two weeks ago (I couldn't put the thing down, honest), this is a wonderful book that explores codes not necessarily from a codes and codebreaking standpoint, but from a historical perspective. Singh weaves a compelling narrative about why codes and codebreaking were important, and outlines the leapfrog game that codemakers and codebreakers have played for the last eight hundred years or so.

    IMHO Singh really does a fascinating job of writing this book. There are only two downsides to this otherwise-excellent book:

    • A digressive chapter on the "breaking" of the heiroglyphics and Minoan Linear B; interesting, but didn't have much to do with codes.
    • After spending the entire book showing how every "unbreakable" code was broken, Singh gets way too excited about the coming "unbreakable" code, Quantum Cryptography []. Granted, it certainly seems secure, but it seems strange to me that he would herald this method as unbreakable when there barely exists a means of transmitting it in the first place.
    Other than these two minor points, I would seriously recommend this book. Also, the book delves extensively into the workings of the Nazi Enigma machine, which is also featured in the upcoming movie U-571 [].


  • Cryptography is interesting to us geeks because it is the combination of two things that we love: mathematics and programming.
  • Funnily enough the law that makes it illegal to export encryption hardware/software explicitly exempts publications (books, magazines, and academic papers) from the restriction.

    This led to the strange operation by which the international version of PGP used to be created. The current US version's code listing was printed out on paper and this was legally exported. It was then OCRed back into electronic form and then manually examined to correct any OCR mistakes. This could then be compiled to create the non-US version.
  • Source code in electronic form (on disk etc.) is not exempt which is the reason that PGP had to go through the process of printing it, exporting it, and OCRing it.

    This is why Applied Cryptography's source CD is not shipped with the book as it would be illegal to export the CD without a license (but not the book containing the same information printed out).
  • Cryptorgaphy was invented by Almarga Newi as far as we know it. It has had an interesting shift to the left of our time span, we had absorbed the mechanisms since the early 19 hundreds when snails were around. But yes, we were there.
  • >> According to the leader board, 8 out of 10 of the codes have already been broken, so get going if you wanted to participate in the last two!

    I think it would still be worthwhile to participate. As I recall, the first 4 or 5 codes were somewhat trivial. Also, each code is something like an order of magnitude harder to break than the one previous to it. It may be years before the last two codes are broken. If all ten codes are not broken by October, the contest will strech to the year 2010.

  • I picked this book up for Christmas (along with Cryptonomicon and Carlin's Brain Droppings). I HIGHLY recommend it to anyone interested in crypto. I agree with some previous posters that the Linear B the Navajo Code Talker chapters were probably the most interesting out of the whole book. Damn codes at the back, they're still stumping me! Well some of them, I finished the first three pretty well. My next challenge - read The Elegant Universe and Six Easy Pieces. I WILL understand relativity!
  • If you have read the book Cryptonomicon one of the characters is named Enoch Root. He is part of the Societas Eruditorum. You may or may not know this already.

A verbal contract isn't worth the paper it's written on. -- Samuel Goldwyn