On: Google have declared Droidscript is malware

[dTal]

And who owns the keys to those things? You, or the manufacturer?

[kube-system → dTal]

Many vehicles have the keys stored in their ECU/Immobilizer signed/encrypted with the manufacturers' key.

There are some (mostly older) where you can directly reprogram the eeprom but those cars are easier to steal, because anyone can also do this.