Desktop application validity

Question

I am creating a desktop application using AIR. In that application user is allowed to download some resources which have life span of 2 days. I am storing the date when the user is downloaded.

But how can i check whether the date is passed 2 days or not? Right now I am checking with the current system date.But when the user changes the system date to back, it will start to work which i dont want.

How the desktop applications say like flex builder and all having trial period.? How are they tracking the dates remaining?

~Umesh

Answer 1

In our application we store a license file on the client machine which stores the date the product was installed and has a counter (so only days the user actually opens the application causes a decrement). We also expire the license if the system date is tampered i.e. if the date < date the product was installed set the counter to the max days allowed. (to punish cheats :))

You could implement a similar solution or even just ignore the license and store the settings in the registry.