Today’s Math Monday begins a multi-part series on the columnar transposition cipher.

We return to the series on columnar transposition ciphers to discuss permutations, how CTCs can be thought of as permutations, and some questions that this connection opens up.

Oranchak, a 46-year-old software developer in Virginia, said the 340 is what’s known as a transposition cipher. Most ciphers used today by computers rely on mathematics to scramble messages.

After reviewing the terms with students, write a different one-line cipher on the board, using the above key, for the class to solve. Write substitution and transposition ciphers.

Experts believed it was a transposition cipher but were mystified by the arrangement of strange markings.

The key breakthrough, according to the magazine, was Blake’s idea that the cipher is simultaneously a homophonic substitution cipher (in which plaintext letters map to more than one ciphertext symbol) ...