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  1. #1
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    Unanswered: Double Playfair Cipher

    See the attachment for a description of the Double Playfair Cipher. Will a kindly programmer write a program to crack it automatically as described?

  2. #2
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    Sep 2004
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    I doubt it.
    Darasen

  3. #3
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    Sep 2003
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    Doubtful

    One lives in hope.

  4. #4
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    Provided Answers: 59
    j Reardon
    a brief question Why would you want a developer to do your coursework for you?
    In any event If you were going to write this you'd hardly use VBA

  5. #5
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    Why not?

    This is not coursework.

    I am not a student and I only know a little about programming.

    I have presented the problem as a challenge to any willing programmer and the outcome would be of great interest to me. I don't see why one should not use VB for this.

  6. #6
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    VB yes, VBA no, there is a differenece, and arguably it has very little to do with databases

  7. #7
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    Sorry if I asked for too much.

    I apologise if this is the wrong forum but not for asking the question.

  8. #8
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    Sep 2003
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    Quote Originally Posted by JLR
    See the attachment for a description of the Double Playfair Cipher. Will a kindly programmer write a program to crack it automatically as described?
    And let me guess ... You just want to see it done right?

    Not in a million years ...
    Back to Access ... ADO is not the way to go for speed ...

  9. #9
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    You are probably right

    I seem to have asked for too much, mea culpa.

  10. #10
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    Nov 2004
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    34
    I've think I'm nearly there with a program in VB NET, could you post the solution to see where I'm going wrong?

  11. #11
    Join Date
    Sep 2003
    Location
    London, England
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    Excellent

    I have no program to solve this but I do know how to crack the code manually. I have tried to explain my method in the first attachment.

    I would greatly appreciate it if you were to post your attempt at a program(maybe as an attachment). If it is close to working I will certainly try to discover where it is going wrong.

  12. #12
    Join Date
    Dec 2003
    Posts
    268

    More examples

    I want some more examples. I got it and it is working with the example. and it seems to be workign correctly. AND I did it all using VBA and not too much code. I just wanna make sure it is workign correctly.

    If this is for homework I am mroe than willing to help you with it, but I am not willing to just give up the code.

    Anyways, if anyone else got it I would love to exchange code with them. Java, Python, VB, VBA, C++ whatever you used. Just curuios as to some other solutions out there.

    MW

  13. #13
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    Dec 2002
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    Préverenges, Switzerland
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    check out the guy's previous posts: he's running the ??? maths department, he's not a student trying to get homework done the easy way.

    izy
    currently using SS 2008R2

  14. #14
    Join Date
    Dec 2003
    Posts
    268

    That being said Ill throw it out there

    Here is what I got. I am going to work on the cypherer, the method to translate
    shireboundforlondonmessageends to
    tkqikdimbovuxpfmslcpyxzmumlisw

    that should be fun and a little bit of a challenge.

    MW
    Attached Files Attached Files

  15. #15
    Join Date
    Dec 2003
    Posts
    268

    Does both now

    In between writing a paper tonight I decided to give the cyphering (is that the correct word) a shot. Proved to be a little more difficult that I had initially anticipated.

    The major difficulties revolved around the period size (in the instance given; 7) and the total length of the text to ben cyhperd. what I ended up having to do was to create a separate method (the primary method in the cypher class was getting too large) to apply the necessary logic to ensure that the string to be cyphered woudl be able to be evenly distributed amongst two strings that were of even length which allowed for the creation of the lettered pairs. See the code for clarification.

    This is a kind of a slop together. I am sure it could be hacked a little more to be a little cleaner and not so many loops but it works and the methodology is pretty clear as far as how I did things.

    If anyone has any questions lemme know.

    This was a good project. Interesting to try and do in VBA, but it was most definately doable and once the logic of the translation of the letter sets was done it wasn't that hard.

    Note****
    Wow I jsut uploaded the zip and it is only 37k. Not too bad.

    OH, and if anyone finds any bugs, just let me know and I will try and hack them out.

    BTW, in a geeky, sadistic way this was kind of fun.
    Attached Files Attached Files

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