Now that practice challenge 3B has completed, I have a question about the keyword being used. The 3A solution indicated 3B was a keyword cipher, and whilst I was able to decipher using frequency analysis and word structure, I cannot see how a keyword is being applied. The substitution alphabet that I formed is below, but I cannot see any structure to it: I am interested in whether anyone else does!
If you take the substitution pairs (A->d, B->g, etc.) and reverse them, you end up with d->A, g->B, h->C…
Sorting these new pairs alphabetically yields:
The keyword is LOYALTY (repeated letters were removed). In general, the keyword is usually found in the ciphertext part of the mapping. Hope this helped.
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