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Code Book Cipher Cracked
AssFace writes: "The Code Book challenge -- I believe 10,000 pounds was the reward for it, and it consisted of 10 stages of increasing difficulty that mimicked the evolution of cryptography throughout history -- was cracked and there is a fantasitc description all at http://www.simonsingh.com/. Goodbye Simon Singh." It's a cool read, too -- both Singh's own writeup, and that of the Swedes who broke the cipher. Congratulations to the winners.
Get the PDF - Stage 5 is in there in detail. It was a bitch indeed...
"Depression is merely anger without enthusiasm." - Anonymous
The son of a bitch about stage 5 was that technically, it was a cipher of numbers built off of a key text - you use the first letter of each numbered word (for example, 1 2 3 4 5 in this comment would equal Tsoab - To make it worse, sounds like he just used a short text and numbered the letters instead. And it was a LATIN version of the text. (Lots of those were in foreign languages. Ouch)
So it wasn't so much decrypting as finding a key text that fit the numbers. It's modeled off the Beale cyphers, which are three lists of numbers that supposedly point to gold. The second one used the Declaration of Independance as a code text. No one can find the first or third, as I recall.
It's virtually a one time pad if you wrote the key text yourself, and in all other respects, is more a matter of luck in finding the text then skills/techniques used in any of the other ciphers (frequency analysis, familiarity with the cipher) and so forth) - Most groups didn't get this one till much later. Most skipped it for quite a while.
I was looking for some text that might be based in Oxford myself, like a text of Newton's or something. Suck.
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ah honey, we're all resplendent - Bill Mallonee
For those of you who haven't read this book but are interested in cryptography, I can't urge you enough to read it. The challenge at the back is especially enticing. I'm not sure if it will lose its appeal now that the answers are published and known, but for me there was something absolutely special about breaking the codes and knowing that I was one of the few people in the world to have done it.
I solved stages 1 - 6 and 9 (I was on the 2nd team to brute force the Stage 9 DES cipher). Stage 7 was the ADFGVX cipher used in WWI and Stage 8 was the infamouse Enigma cipher used in WWII. For those who haven't had a crack at this, it's certainly worth it. IMO there is nothing quite like revealing a code piece by piece. I was privelaged or lucky enough to decipher some of the hints on the eGroups message board and be one of the first few to solve Stage 5, and the elation from seeing--for the first time--what only a few people have ever seen is nearly indescribable.
In summary, this was a wonderful book and an excellent adventure. Best wishes to the Swedish smarties who actually cracked Stage 10 (they had to pick between brute forcing triple DES or 512-bit RSA) and to everyone else who contributed along the way. It has certainly been an excellent experience!
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Have fun: Join D.N.A. (National Dyslexics Association)
This is the first time "normal" computer hardware has been used to break a 512-bit RSA key.
The first public break of an RSA key of this size was performed using 224 CPU hours on a Cray C916 whilst the team that cracked the codebook puzzles took just 13 days on a quad-Alpha Compaq beast.
Don't forget, before the export rules were changed around 90%+ of all "secure" SSL transactions on the internet were using 512-bit keys. Scary, huh?
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"Mary had a crypto key, she kept it in escrow, and everything that Mary said, the Feds were sure to know."