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  • [Christmas Challenge 2024] Crack Doppelkastenschluessel-Hex

    From Stefan Claas@21:1/5 to All on Fri Dec 20 21:35:47 2024
    Hi all,

    I recently finished my Doppekastenschluessel-Hex project,
    which is a simplified version of the original German WWII
    cipher, with hex notation.

    For more details check my previous thread 'Seriation'

    Your task is to crack the provided message, which uses
    only one key for encryption, instead of two (default)
    or more.

    The message:

    75 A2 85 D1 84 59 85 2D 25 CB 85 1C 24 70 27 6C
    C5 3C 65 2E 87 6C 8E E7 89 E9 C9 3E 8E 7D 8E D6

    Please note: The message is written as normal text and
    not like plaintext messages from the old days and with
    padding applied.

    The price for the Winner is a set of EFF lapel pins and
    an orginal sticker for the 'age' encryption file program
    and for the Runner-Up an 'age' file encryption sticker.

    <https://1drv.ms/i/s!AjK3D2S6tPVNgSvTOonKu70ci9aX?e=KMZCdb>

    Send your decrypted result to sacenator<at>gmail<dot>com
    and do not post your result here.

    Merry Christmas
    Stefan

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Stefan Claas@21:1/5 to Chris M. Thomasson on Fri Dec 20 21:51:11 2024
    Chris M. Thomasson wrote:
    On 12/20/2024 12:35 PM, Stefan Claas wrote:
    Hi all,

    I recently finished my Doppekastenschluessel-Hex project,
    which is a simplified version of the original German WWII
    cipher, with hex notation.

    For more details check my previous thread 'Seriation'

    Your task is to crack the provided message, which uses
    only one key for encryption, instead of two (default)
    or more.

    The message:

    75 A2 85 D1 84 59 85 2D 25 CB 85 1C 24 70 27 6C
    C5 3C 65 2E 87 6C 8E E7 89 E9 C9 3E 8E 7D 8E D6

    Please note: The message is written as normal text and
    not like plaintext messages from the old days and with
    padding applied.

    Perhaps we need a larger amount of ciphertext?

    That would make cryptanalysis easier, right?

    BTW. For drawing the winners, should they been drawn from
    a random pool of entries, or by first come first serve?

    --
    Regards
    Stefan

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Stefan Claas@21:1/5 to Chris M. Thomasson on Fri Dec 20 22:10:44 2024
    Chris M. Thomasson wrote:
    On 12/20/2024 12:51 PM, Stefan Claas wrote:

    Perhaps we need a larger amount of ciphertext?

    That would make cryptanalysis easier, right?

    I think so. Depends on the algorithm. If it's secure than perhaps no so much... The interesting aspect of SCOS is that it's not secure at all.

    Well, only one key is used and it is a double square cipher, i.e. it is basically a monoalphabetic bigraphic bipartite substitution, according
    to Wikipedia.

    BTW. For drawing the winners, should they been drawn from
    a random pool of entries, or by first come first serve?


    That is up to you! :^)

    O.k. :-) Should there be many entries, I choose random and if
    it's only a couple of entrie by first come first serve.

    --
    Regards
    Stefan

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Stefan Claas@21:1/5 to Chris M. Thomasson on Fri Dec 20 22:51:35 2024
    Chris M. Thomasson wrote:

    Another aspect of SCOS. Richard wanted us to derive an algorithm. If not
    just outright copy his C impl which he encrypted and posted. I pissed
    him off a bit in that thread. Sigh. Damn!

    Well, now he can participate in this challenge... (assuming he is still with us)

    --
    Regards
    Stefan

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)