Background
I\'ve had problems for quite a while now with players cheating in my android game. For a strict single-player game this wouldn\'t be a big is
You can store life in X number of variables and the real value will be the sum of them (always calculated dynamically). You randomly choose which one to update. On top of that You can add some consistency check and it becomes extremely hard for cheater to realise what and how to change it.
The consistency check could be a simple rule that 1st, 2nd and 3rd variables are in growing order for example and the 4th is the smallest. It will take someone good while to figure this out with this tool.
Yoy can also get more creative and mix in some encryption etc (the way you mentioned) on top of that. Then it becomes second to impossible unless someone has your code.
EDIT: Add 100 random variables that change all the time with random names (or positions in the array, to make it easier) and then good luck for cheaters looking for the right ones. And make it all dynamic so every time they have to crack it again.