Using certificates will give you an additional layer of security for your MQTT communication.
To integrate MQTT with certificate into Home Assistant, add the following section to your
# Example configuration.yaml entry mqtt: certificate: /home/paulus/dev/addtrustexternalcaroot.crt
‘auto’ or the certificate authority certificate file that is to be treated as trusted by this client. To enable a secure (TLS) connection to your server you must define the ‘certificate’ configuration parameter. ‘auto’ uses the certifite CAs bundled certificates. If a file is specified the file should contain the root certificate of the certificate authority that signed your broker’s certificate, but may contain multiple certificates. Example: