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Have a question about the National Cipher Challenge and unable to find the answer here on the site? Post it here, and if you know the answer to someone’s question, feel free to reply.
In past years there has been a non-compete option at registration, for older players and ineligible enthusiasts. I see no mention of it this year. How will you filter the competitors from the other participants?
Looking forward to these challenges!
We will ask about eligibility if someone is potentially a prize winner using the new Message system (which is there so we can contact competitors without having to ask for an email address). Otherwise we are working on the basis that we don’t need to know.
Harry
Hello Harry,
In many foras, we can see all messages written by somebody with a click on his pseudo. Why this is not implemented here?
Sometimes, I look for a particular message of which I know the author but it’s difficult to find it.Hey Harry,
Are we allowed to use online cipher tools to help solve these challenges or do we have to crack them manually?
You can use tools, but you are supposed to write them yourself! After all the idea is to learn how to break ciphers, not to get someone else to break them for you. Having said that, we don’t mind if you use an online frequency checker. We don’t mind it so much we include one here on the site, so that isn’t cheating. Similarly you can use our Caesar wheel and affine shift tools in the BOSS cipher tools section.
You should feel free to research how to break ciphers online, but the idea is to show us what you have learned.
It is more or less impossible to break the harder parts of the competition using standard tools anyway, and we ask prize winners to tell us how they cracked it, so if you want to win a prize you definitely want to avoid relying on other people’s work.Hope that is clear enough.
Harry.
PS – if something feels like it might be cheating, it probably is.
@Code-breaker, here is a list of books about programming for classical crypto. I haven’t read any of them,
so I can’t make any strong recommendations. They are also quite old, so you might want to learn Python on-line
at the same time (not that hard).Simon Singh, The Cracking Code Book (does it focus on computing?)
Andreassen, Karl, CRYPTOLOGY AND THE PERSONAL COMPUTER
Aegean Park Press #47, 1986. 157pp. ISBN 0 89412 144 8Andreassen, Karl, COMPUTER CRYPTOLOGY – Beyond Decoder Rings
Prentice-Hall, 1986, 243pp.Bennett, W.R, SCIENTIFIC & ENGINEERING PROBLEM SOLVING WITH THE COMPUTER
Prentice-Hall, 1976. ISBN 0-13-795807-2Bosworth, Bruce, CODES, CIPHERS AND COMPUTERS
Hayden Books, New Jersey, 1982Deavours, C.A, CRYPTANALYTIC PROGRAMS FOR THE IBM PC.
Aegean Park Press #29. 1987. 44p plus floppy disk.Foster, Caxton, CRYPTANALYSIS FOR MICROCOMPUTERS
Hayden Books, New Jersey. #5174 1983, 333 pages. ISBN 0-8104-5174-3Lauer, Rudolph F, COMPUTER SIMULATION OF CLASSICAL SUBSTITUTION CRYPTOGRAPHIC SYSTEMS
Aegean Park Press, PO Box 2837, Laguna Hills, CA 92654. C-32 1981, 111 pages. ISBN 0-89412-050-6Thanks Madness, I’ll try and find some of those books. Do you (or anyone else) know any websites/resources I could use to learn cryptography with python? I’m pretty new to the cipher challenge and I don’t really know how to do any of the challenges after challenge three!
You might try
http://practicalcryptography.com/
I learned a lot from that site, but I never used any of their code.My own book is being held hostage by Harry, possibly because it reveals too many secrets.
http://inventwithpython.com/cracking/ uses Python 3 to crack various ciphers
I would like to amend my last comment. I have looked at more of CCwP, and now I see that they give you
ALL of the code for the various projects. While it’s nice to have examples, when they give you everything
you don’t have to put in the work and do the learning. So be careful if you decide to start with this book.I just downloaded Cracking Codes with Python, and looked at the sections on detecting English, hacking the
substitution cipher, and hacking the Vigenere cipher. They do things differently than I would do, but they
include a lot of Python code. Also, they discuss only one kind of transposition cipher (not the one in
challenge 4B, btw), and only one polyalphabetic (the Vigenere).I would say that it would make a good introduction to someone on your level, @Code-breaker, who is just
starting to learn Python and crypto. After CCwP, maybe Harry will let you read my book.I forgot: There is an O’Reilly book Learning Python by Mark Lutz. If you search for it, you can find
free and legal downloads of the not-quite-latest version from O’Reilly’s website.Hello,
Considering there are less challenges this time, it is more likely for someone to get full points. How will the winner(s) be decided if they solve the final challenge within the same point boundary? Would this be based on time completed or the quality of their work on how they solved the challenge?
Thanks![We will look at the time taken to complete the 7B, and then ask the top competitors on that basis to submit a description of how they cracked the final challenge. We will then select winners from among those submissions. Speed of submission for 7B will play a key role, but is not in itself sufficient to guarantee a prize as we need to be clear that the speed was the result of the hard work of the competitors themselves.
Hope that clears it up a bit. Harry]Hello, I have a question regarding scores. For all of my submissions, regardless of when, it shows that my team receives 100 points, even if the cipher has been submitted before the first points boundary. Is this normal, or is there a problem here? Thanks.
[Excellent question. The points you see are for accuracy (100%) the ones you don’t see are the time band points, which we use to score part B of each challenge and the overall part B leaderboard. You can infer them from your position on the board in each round. Don’t worry we haven’t forgotten them! Harry]
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