Hi neocreed,
I use a simple method to encrypt my values. Do some math on the value like ln, log10, etc. plus some multiplication, division. Do that twice using a different approach for the second one, then send both values to the php file, reverse the math and compare the two values, they should be the same.
This is quiet difficult to hack, since you would have to find both math methods and any simple try to fake the values will result in inequality of the two values, so you know they are invalid.
Regards
Frank