RSA

A lock anyone can close

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• RSA: public key $(n, e)$, private key $d$ with $ed \equiv 1 \pmod{\varphi}$.
• Encrypt $c = m^e \bmod n$; decrypt $m = c^d \bmod n$.
• Its security relies on factoring being hard; quantum computers threaten it.

Steps

1. Public and private keys
2. Building a key
3. Find the private key
4. Encrypt
5. Why it works
6. Breaking the toy
7. Quantum threat