

make it so that every user owns their data collected by this and its all encrypted with some key private to that user. Then have only t he user be able to share the data with others. Or rather dont collect it all to some central database but have everyone make their own for private use.
But I dont think this is very good idea in the first place. What use is it to regular people to track others licenceplates? Who do you share the information with, the government? In usa they would just gleefully abuse it, in eu using it would just be horribly difficult for everyone involved due to legal issues and having private database about other peoples information isnt allowed or it requires somekind of registration i think, or was that only in finland.? In fact this might be outright illegal system in eu. Other places likely have superior database already.
And in the end, the whole thing will likely just be taken from you by force if nothing else works. Maybe some corporation will buy you out or maybe government will just seize it. No way they would just ignore something like this if it has any use to them.
So please be really careful how you do this so you dont end up making things worse for everyone by mistake. At least have some safeguards so you can destroy the whole thing if you need to so it cant be abused if anyone trys to take it from you.
Its nice idea, being able to track stuff independently, but i think it might belongs to some different, more friendly world, that is not this awful place we have to live in.
I hope it works out as you want