There are four major ways to communicate with MQTT servers: MQTT, secure MQTT, MQTT over WebSockets, and MQTT over secure WebSockets. WebSockets are typically used when websites communicate with an MQTT server on the frontend.
Let's talk about the secure element in secure MQTT and secure WebSockets.
This book is all about prototyping: trying things out and failing (or succeeding) fast. For this, we don't care too much about security, as properly securing our prototypes would increase complexity and require more time. But, we should understand how to establish a basic level of security, and know when basic security is not enough.