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"Technology reveals the active relation of man to nature"
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File: 1626954376467.png (38.77 KB, 769x458, cards.png)


have u ever considered that a deck of playing cards
can be seen as two alphabets that can be freely re-arranged

playing card ciphers –
paperless simple cryptosystems
fit in your pocket

initial randomization of alphabets in 7+ shuffles


File: 1626954642208.png (21.72 KB, 907x400, ClipboardImage.png)



i think we should all just train like chinese kids and be able to do huge math in our heads and just mentally compute RSA


I played around a bit with chaocipher and came to a realization: You could use a simplified alphabet and set aside a few cards to use them as a flags for numbers, case, punctuation and whitespace.
Arranging them in a separate stack minimizes mental overhead, when adding the values and allows for another simple permutation.
I decided to use 24 cards in my large stacks, because it's a nice base and with 1 global flag, you get just enough symbol space for: lowercase (without c and j), uppercase and " [email protected]'"←→()-+/\<>^_%?".
My deck had a third joker, so I used it as a global flag, that is toggled, when the top card of the small stack is a joker. Thereby you could use 3 additional spaces for base 24 numbers and maybe regional symbols or mathematic/scientific notation.

Secure RSA keys should at least be 128bits long (39 decimal digits). I don't think any human can do multiplication with those https://www.recordholders.org/en/events/worldcup/2018/results.html
By using a higher base, you could try to make the numbers more memorizable (26 digits with base 24, 24 digits with base 32, 23 digits with base 64, 11 digits with base 5040).


>randomize the alphabet
That's a very primitive and poor cypher. All your adversary needs to do is detect common word patterns which narrows down the field of possibilities until you can brute-force permutate through them. This can be fully automated with the help of a "dictionary". In cryptography breaking such a cypher is homeschool work for the intro class tier. Using cards is clever as a way to disguise the existence of communication, but once your adversary catches on it's basically over.

A much better but also primitive cypher is to replace full words with some other completely unrelated words (or cards, why not). That completely removes the above vector of attack where your adversary could simply analyze word patterns. Even if your adversary knows you're talking in code they still can't so easily figure out what you're talking about.

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