This is an explanation of the Cryptography challenge 'New Caesar' from CyLab Security Academy (formerly picoCTF). You are provided with a short ciphertext and the single Python script that created it.

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 ...

In the winter of 54 BCE, a javelin flew into a besieged Roman camp in Gaul with a letter tied to it. The camp was commanded by Quintus Tullius Cicero, brother of the famous orator, and enemy forces ...

plaintext AND to decrypt a ciphertext. That is four operations, and most resources show one. Every sheet here does all four. 8-bit ASCII code is given, and so is the one-time pad’s; the student poses ...