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Archive of Old Challenges

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  • #40811
    Madness
    Member

    There is an archive of old challenges for you all to use as practice at
    https://github.com/themaddoctor/BritishNationalCipherChallenge
    It exists because the official website only goes back three years, and it can be difficult to dig up the old challenges from archive.org and other places.

    The archive contains all ciphertexts, and all the information you need to solve them, except for these two missing files:
    FialkaSettings.pdf [2005]
    cards.png [2010]
    If any of you belong to a cipher club with a long memory, and have these files, please share them. Thanks in advance.

    #44765
    Cryptoismus
    Member

    I have a copy of the FialkaSettings.pdf file. As for the cards.png file, I don’t have that file but I do have some screen shots of the cards as they were revealed over the days of the challenge. Let me know How I can get these to you.

    #44749
    Madness
    Member

    Harry,

    Can you fill in some missing keywords for transpositions from previous years?
    Here are the ones I am not sure of, or have no idea. Thank you!

    (permutations start at 0, not at 1)
    2003 #8 4,3,6,1,0,7,2,5 MISS DISASTER ?
    2006 5A 2,4,1,3,0
    2009 4B 3,0,2,4,1
    2011 4B PORTA ? PIANO?
    2012 7A 2,4,0,5,3,1 ELATED? ERASED?
    2014 7B 2,0,1,4,3
    2016 4B 0,4,3,1,2 or 2,1,3,4,0 BYTES?
    2016 5B 4,0,1,3,2 VACUO? VIRUS?
    2018 6B 1,0,4,3,2
    2018 8A 2,5,7,3,4,0,6,1

    #44819
    Harry
    Keymaster

    I am not sure if I can. I will try to dig through the old files to see what we still have!
    Harry

    #44827
    Madness
    Member

    @Cryptoismus

    Please go to this page and attach your files to a message by dragging them onto the message.
    https://github.com/themaddoctor/BritishNationalCipherChallenge/issues/6

    Thank you!

    #44928
    Agent-p-z
    Member

    Hi, Madness.

    For 2011 7B, you have it down as a route transposition cipher but I don’t believe this is the intended solution. 2011 7A mentions that 7B is a ‘columnar transposition with a twist’. Thus, I believe the intended solution for 7B is a Myszkowski transposition with key ‘ABCDE EABCD DEABC CDEAB BCDEA’.

    #45023
    Madness
    Member

    @Cryptoismus
    Another user has asked about seeing your screenshots. Do you have time to upload them?
    Much appreciated.

    #44952
    Madness
    Member

    @Cryptoismus You can also upload the screenshots that you mentioned. I will handle the
    editing etc. Thanks.

    @Agent-p-z Thank you, I will look into those things.

    #44953
    Madness
    Member

    @Agent-p-z
    Sometimes there are several ways to look at the same cipher. You might be correct that it
    is a Myszkowski transposition. I am still working on coding that. But the key you suggest
    is just too complicated for what we should expect; also notice that it has a pattern in it,
    suggesting that there is a simpler underlying idea, especially since we are expecting a
    meager “twist”. I suggest that the simplest solution is a columnar transposition in which
    each column is rotated (shifted down) by one more than the preceding column. Thoughts?

    #44954
    Madness
    Member

    @Agent-p-z
    Like taking a scytale and twisting it.

    #45031
    Agent-p-z
    Member

    I’ve looked at the updated solution you put up and I agree that that is most likely. I guess the literal ‘twist’ makes sense. Thanks for clarifying.

    #45161
    Cribbage
    Member

    Many thanks to Madness for the archive of previous Cipher Challenges – it’s nice to have something to do when Cipher Challenge 2020 is still so far away …

    I may have missed something but I have a slightly more complicated answer for 6B from 2009. The given answer is “keyed substitution cipher, key = MONHIERSTUVWXYZABCDFGJKLPQ, keyword = MONHIER”. I get the same key but I think it is a homophone substitution cipher, where every plain text letter is replaced either by the ‘MONHIER’ key letter, or by its ‘opposite’ letter in the alphabet. Hence a plaintext ‘a’ could be either ‘M’ (from MONHIER) or ‘z’ (its opposite letter), a ‘b’ could be either ‘O’ or ‘y’ etc.

    Cipher Plain
    M a
    z a
    O b
    y b
    N c
    x c
    H d
    w d
    I e
    v e
    E f
    u f
    R g
    t g
    S h
    s h
    T i
    r i
    U j
    q j
    V k
    p k
    W l
    o l
    X m
    n m
    Y n
    m n
    Z o
    l o
    A p
    k p
    C r
    i r
    D s
    h s
    F t
    g t
    G u
    f u
    J v
    e v
    K w
    d w
    L x
    c x
    P y
    b y
    M Z
    a z

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