This week I want to introduce a topic that’s of interest to me, and that is the columnar transposition ... which is where this cipher gets its name. To get the encoded message, copy down the ...

This week it’s me again, and we’re going to get back to the notion of A CTC is just one of many transposition ciphers, which is one of the basic cryptographic primitives. Transposition ciphers ...

Cryptanalyst Jim Gillogly created them using the Playfair, Double Playfair, and Double Transposition ciphers, respectively. In the opening paragraph for each challenge, we link to instructions ...