HTTP vs HTTPS

Part of the Web course

Picture yourself on the free wifi at a coffee shop. Someone else on that same network, running nothing more exotic than a packet sniffer, can watch every request your laptop sends. If your browser is talking plain HTTP, that person can read your login form as you type it, see the session cookie that keeps you signed in, and copy every URL you visit. Nothing about HTTP is designed to stop that.

HTTPS is the fix. It is the reason your browser shows a padlock instead of a warning, and the reason "is this site HTTPS" became the first, cheapest security check anyone can do. This lesson is about what that padlock actually buys you, and, just as importantly, what it does not. ...