How HTTPS Secures Connections: What Every Web Dev Should Know
blog.hartleybrody.com/https-certificates
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
How was data protected? How can a client and server create a secure connection if someone was already listening in on the wire? What is a security certificate and why do I need to pay someone to get one?