- cross-posted to:
- cypherpunk@infosec.pub
- cross-posted to:
- cypherpunk@infosec.pub
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A substitution cypher, a very predictable one at that.
Plaintext
he who must not be namedI don’t have the faintest idea what a substitution cypher means 😂
Found this system in Reddit - been using it once in a while for fun!
Probably Voldemort.
All substitution ciphers are weak. When I was 10, I was on a camp where we “discovered” an encrypted page in a night game and the next day, a game of searching for scattered “clues” (substitution pairs) took place. In the meantime, I had deciphered the message using frequency analysis and guesswork so the pissed-off organizers created another page with the same cipher for our team to solve. I was grounded for “spoiling the fun” while others were playing, and our team came last because they had to wait for their page.
Frequency analysis at 10? Lol sure.
I was a nerdy kid, and I played numerical crosswords. I had read Kjartan Poskitt’s books including Codes: How to Make Them and Break Them (in Czech, of course). I only remembered the first few vowels and one consonant from his list of top characters but that was enough because
- I had enough time for guesswork (took me about 90 minutes, I could do it in about half the time now with more experience)
- there were recurrent words relating to the theming of the camp
- Czech letter frequencies are more lopsided than English (we barely use F, G, Q, W, X)
- one page is good enough to get good statistics, and the two or three top letters did match expectations
- I could technically somewhat accurately recreate Kjartan Poskitt’s (actually the translator’s) frequncy table using a Harry Potter book I had (turned out not to be neccessary, it would have been time-consuming)
Some cipher creators actually preserve diacritics. Seeing a symbol like έ, ≗ or ⊔̌ would be a giant giveaway because we only have the following diacritics: ČĚŘŠŽ (+ rare ĎŇŤ), ÁÉÍÝ (+ rare ÓÚ), Ů. The organizers had converted the plaintext to ASCII before encrypting it but this is still weaker than treating letters with diacritics as completely separate.
I don’t think my story is too unbelievable. Some kids just learn things faster/slower than others. I learned to write in all caps before I could wipe my butt (I’ll leave it to interpretation if I was an early writer or late-ass wiper).
