Secret messages have shaped history — and breaking them has shaped mathematics. In this afternoon workshop in Neuchâtel, upper secondary students start by cracking Caesar and Vigenère ciphers with frequency analysis, pencil in hand, before discovering why these methods fail against modern cryptography.
The second part builds up the ideas behind RSA step by step: modular arithmetic with clock faces, prime numbers as trapdoors, and a full key exchange performed by the whole group with nothing but paper cards. No programming experience is needed, only curiosity and a taste for puzzles. Places are limited to 24 participants; registration by e-mail.