MQTT TLS connection to mosquitto broker

Question

Hello , I am trying to connect my wizfi360 to mosquitto broker in a secure way. I have previously asked about this :MQTT SSL security I have looked at the AWS and AZURE examples. However, in my product I am using a very small 16 bit MCU and will not be able to implement your code/ method of sending certificates using sockets. Is there a way to load the mosquitto certificates into your flash memory, through an AT command? That would help me connect easily. Kind regards Hari

austin · Answer

Hi @haricane00 As mentioned before, entering certificates other than the Root CA is not supported when connecting to MQTT SSL/TLS. Therefore, if you want to enter certificates, you have to implement that part on the application and use it. If entering the Root CA certificate is sufficient, please refer to the ‘AT+CASEND’ AT command in the document below. https://docs.wiznet.io/img/products/wizfi360/wizfi360ds/wizfi360_atset_v1118_e.pdf

haricane00 · Answer

Hi Austin, Thanks for the response. Maybe entering a ROOT CA cert is sufficient for me. If I load that via AT+CASEND command, will it set stored in flash and will it persist across reboots, or will I have to send it each time wizfi is powered up? Also I came across this document on your website: How to connect WiZfi360 to AWS: wizfi.github.io Connect WizFi360 to AWS IoT using AT Command | WizFi360 Getting Started Is this method working? This seems to allow loading private key and device cert into wizfi360. How? Kind regards, Hari

austin · Answer

Hi @haricane00 Yes, if you enter the Root CA certificate with the ‘AT+CASEND’ command, it is stored in flash and remains in flash after reboot. The command to enter the private key and client key used in the guide document you shared are commands used to connect AWS IoT Cloud, so it cannot be used for general MQTT connection.