As others have said here its not physically mining on your phone but a simulation.Its more like an airdrop that gives out coins to people who run the app and it calculates how much you would earn based on your phones specs and time used.Seems to be legit and people have gotten there coins but my problem is the app keeps stopping and needs to be reset so I am only earning about 5ETN a day instead of the 10ETN if it was working properly.Hopefully updates will make this more stable.You are still getting low value coins for no effort which may be worth a bit more in the future.