Category Archives: Ciphers

Cipher 71: Monoalphabetic II

As promised, the fourth season of cp4space ciphers has now commenced. Here’s a monoalphabetic substitution cipher with a nine-letter plaintext containing a man’s name. The password for the solvers’ area is the person who killed that man, entirely in lowercase: F B’ … Continue reading

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Cipher 70: Wild goose chase

Once again it is Cipher Tuesday, and this time I actually have a cipher to release: 1. Frg hc n purffobneq va gur fgnegvat cbfvgvba. 2. Ba n cvrpr bs 90tfz N4 cncre, qenj gur Qlaxva qvntenz bs gur fdhner … Continue reading

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Cipher 69: A void

Before this week’s cipher, I have a few late items of news: Professor Stephen Hawking has recently committed a Eugenia Cheng, publishing a formula for the perfect penalty shootout. There is a biographical movie about Srinivasa Ramanujan, unsurprisingly entitled Ramanujan, … Continue reading

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Cipher 68: Conjugation

I have become aware of several brute-force dictionary attacks on cp4space password-protected areas. As such, this password will most certainly not be in the dictionary, and thus a brute force search would require testing 8 031 810 176 different lower-case … Continue reading

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Cipher 67: Dyslexic philosopher

This multi-stage cipher was considerably difficult to design; indeed, the encrypted message had several fortunate properties. Anyway, firstly we have a bunch of crossword-style clues: Secondly, here is a grid of digits: And here is the third and final stage: sqrt(N) … Continue reading

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Cipher 66: Hash inversion

Yes, this is designed to be deliberately difficult: 15fbaa066a407be6ca5d86838b756d3d Enjoy…

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Cipher 65: Melencolia

Firstly, congratulations to the British EGMO team (Olivia, Kasia, Katya and Eloise) for their impressive performance, coming eighth out of 29 competing teams. Apparently the competition was held in the same five-star hotel in Antalya enjoyed by a previous Balkan … Continue reading

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