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 ...

This was one of the most secure hand ciphers used in the Second World War. It was used by both the Allies and the Axis, and served both well. Its main weakness was that if the attacker intercepted two ...

Last week’s installment on columnar transposition ciphers described a formula for the underlying permutation for a CTC. If we assume that the number of columns being used divides the length of the ...

Introduction to ciphers and substitution. Alice and Bob and Carl and Julius: terminology and Caesar Cipher ; The key to the matter: generalizing the Caesar Cipher ; Multiplicative ciphers ; Affine ...

Here's your chance to crack ciphers similar to those Bletchley Park's codebreakers faced during World War II. Below, we present three ciphers of different levels of difficulty, from easiest to most ...