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 ...

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 ...

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 ...

In cryptology, the discipline concerned with the study of cryptographic algorithms, a cipher is an algorithm for encrypting and decrypting data. Transposition ciphers keep all the original bits of ...

Introduction If you need to send a secret message to a friend, how could you prevent other people from reading it? One way is to encrypt the message—that is, use a secret code that only you and your ...