# A new kind of cipher

While not a wholly original idea (I stole it from somewhere–just can't remember where), it should be resistant to classic cryptanalytical techniques. However, I have my doubts about its actual, real-world security. Therefore, I thought: What better way to test it than a real-world test by letting the great minds at puzzing.stackexchange take a crack at it. Any hints I'd give I'm afraid would be too much, so no hints for now.

The task is pretty straight-forward, just decipher the following phrase:

T | | F |\/| ^ 6 L C | | | 8 P D S ∆ R F G O L! E /\ |V| | G U Q G G T E D 4 G 5

This seems to be a mixture of l337sp34k and a substitution cipher, with several possible ciphertext substitutions for the plaintext letters.

The first couple of words can just about be read as they are, but the text is a bit short for solving the substitutions by brute force: the last two words don't help as much as usual, because they just random dictionary words. However, since this plaintext has been used before, we can be pretty certain the answer is

The magic words are squeamish ossifrage.

• Well color me surprised. Interesting, I was thinking this was quite unlike a substitution cipher, but I suppose you are right, thinking more abstractly, it could be treated as one, and a similar strategy could be used to attack it. Apr 25, 2021 at 19:09

@Bass has solved this puzzle. Although, they didn't quite hit on the way I had intended for it to be solved, but what matters is they arrived at the correct solution.

See below for how I intended for this puzzle to be solved, I feel this is where the novelty in it lies:

The idea is that substitution characters are chosen such that the top half of the letters don't change, so that one only needs to cover up the bottom half of the characters to be able to see the message, as your brain is pretty good at filling in the blanks. Although its apparent to me now, that the phrase I choose was not the most exemplary of this phenomenon:

• Does anybody know of what this kind of 'cipher' is called? There has to be a name for this concept. Apr 25, 2021 at 21:53
• I don't know if there is a name for this kind of cipher. At least not in the cryptographic field of study. I think it's more in the brain teaser word puzzle category. It is still a cool concept though. Apr 27, 2021 at 20:02