Hi,
I have a tecnoalarm TP10-42 “smart” system that can be controlled using “myTecnoalarm TCS” app.
Tecnoalarm provides Alexa Tecnoalarm Skill but I have no Alexa device and I’d like to integrate directly into Home Assistant.
Using Android studio + HTTP Toolkit I was able to capture and decrypt https communication generated by app. 
so I think that could be tecnically possible to create a custom integration.
Note: I’m totally new in home assistant, this kind of activity have some legal impact?
Note2: there was another thread related to tecnoalarm but it was focused to hardware part: Tecnoalarm Homeassistant integration