1. Why do we need HTTPS
Start reading here. If there is only one thing that you take away from this comic, let it be this one.
2. The keys
To understand how HTTPS works, you have to know how symmetric and asymmetric key encryption works. It sounds like big words, but really it's not.
3. The handshake
When you browse to a HTTP secure site, your browser and the server where it connects to have a secret handshake. We break this down and bring it into the real world so you can greet your friends with the secret handshake.