Hi,
Simply use the current date time using the action "getSystemDateTime", that's enough to be ok with checking elapsed time on a device safely.
so for example, have your game check for the unix time ( 1970/1/1) so that all games use the same base and then you can expect a pretty good synchronization of events if you have a leaderbord or share some common features across users.
If you are concerned about cheating, then you need to go for https access, cause I can sniff your call to your server easily and corrupt the return and cheat this way. So then you would need some more obfuscation and even some data hashing to provide additional layers of security.
the best way could be that you simply pass data to your server and the server simply check the time of the call itself, so your game doesn't need to care about the time locally. Have you experimented with this?
Bye,
Jean
Bye,
Jean