This might be one of those "not answerable" or "just opinions"-questions but I thought I'd give it a shot.
I'm developing an app with health care information with a friend who's a doctor. The basics of app are done and the information in the database is shaping up so now I've come to the question of wether, and if so how, I should restrict access to that information to just my app. The question of if is one I can answer, but any opinions are welcome. The question of how is where I need your help.
The app is written in Java on Android and the backend in Django, what ways do you see for restricting access to the backend so that other scripts/apps can't access it? One idea I had was for the phone to request an api key on first start and bind it to the IMIE number which I think is unique for each phone, then keep track of those tuples on the server. We(as in I) will likely port this to iOS at some stage, so it needs to be fairly cross-platform, I thought about binding to google accounts instead of IMIE number before.