A simple way to improve the security of our edge analytics applications is to use the SSL port when communicating with an MQTT server. The following is a diagram of an SSL connection:

As we can see, when a client requests a connection to a secure website (using https in the URL), a certificate is sent to the client once the DNS records are checked and the request made. It is through this certificate that a secure connection is made and established with the client and the secure website.

In order to use SSL for our smart doorbell application, we need to use the SSL port displayed on the Instance info page in CloudMQTT, as shown:

The drawback to using SSL is the extra work that is carried out between the client and the secure website in the form of handshakes and encrypting and decrypting messages. This leads to a performance hit as the extra steps require more time.