However, Agent Madeleine numbered the duplicate A's and L's from right to left instead of from left to right, so it would be the equivalent of replacing the keys with MCHBTUNDILA and CUMLBTJNDIKA, ...

We all have secrets to keep. Those secrets could be personal dirt we want to keep from others, or they could be something as mundane as our credit card numbers or medical histories. But all of us have ...

It’s been a couple of Math Mondays since we last looked at columnar transposition ciphers, so let’s jump back in. In the It’s been a couple of Math Mondays since we last looked at columnar ...

The Double Playfair is an extension of the Playfair to use two separate keys and to encipher each pair of letters twice. The German police made the mistake in late 1941 of switching from the rather ...