During the installation of the App, this should generate a random number
I mentioned this subject some time ago and would like to return to it to see if I can explain it in a way that makes sense.
Besides that it is foreseen, that by sending the name of the IoT's that are registered in the Gui-O App, following the @init, it would be important that during the installation of the App, it should generate a random number, it doesn't need to have more than 4 digits which would be associated with that App installation. Whenever the App be installed on another cell phone, a new random number would always be generated. This number should also be sent together with, for example, "@init + Iot name + App installation number".
Only in this way it will be possible to manage the access permission later on the Mqtt Broker.
As it is important, please think if and how you can do this and when.
For the situation of working with Firebase, this need is the same.
I hope I explained it well
@sato As I've mentioned, you should not use the generated number / uuid, since it is not retained if the user re-installs the application. This has nothing to do with MQTT protocol as this would be included at the payload level (MQTT is data-agnostic, i.e., you can send anything you like in the payload field).
You should use username and password to control your users. HiveMQ (I do not work for them ) has a free plan, where you can freely add or remove users. See:
I hope I was clear.
I will leave it for later when I can experience a practical example.
If justified, I will return to the subject.