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

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.

To decrypt a double transposition, construct a block with the right number of rows under the keyword, blocking off the short columns. Write the cipher in by columns, and read it out by rows.

Crack the Ciphers by Jim Gillogly Here ... Double Playfair, and Double Transposition ciphers, respectively. In the opening paragraph for each challenge, we link to instructions ...

Experts believed it was a transposition cipher but were mystified by the arrangement of strange markings. Dave Toschi, who hunted and was haunted by the Zodiac serial killer, dies at 86.