IoT (Internet of Things) is all about connecting to the internet and even more about security. Without security and encrypted communication, everyone can possibly see what I send or receive. And this is especially bad if passwords or user names are sent in an unencrypted way. So, encryption and secure communication is key. The solution to that is to use a connection which uses the TLS (Transport Layer Security) protocol, which I want to use for my MQTT communication (see MQTT with lwip and NXP FRDM-K64F Board).
This article walks through the basic principles for secure communication using TLS with MQTT in mind. TLS is the successor of SSL (Secure Sockets Layer), and the two are often used together (TLS/SSL). TLS (as the name indicates) is an encryption on the transport layer: that means that the application layer does not have to implement the encryption itself. Instead, it configures the transport layer to use the encryption protocol.
Read more at DZone