Control date during trial applications

[Fraps]

Most of us creates many softwares that run only for a specified period of time in the trial mode. Once the trial period is expired these softwares stop functioning and demand for a purchase for example.

Anyway many users can cheat the application changing the date in window. Is there any easy way to control that?

[baja_yu]

No..

[techgnome]

There's no completely fool proof system... but you can make it harder.

-tg

[baja_yu]

And however hard you make it, crackers will find a way around it. So be sure to find a balance and not spend too much time/money on it.

[techgnome]

Here's a little something I tossed together in VB.NET...
http://www.vbforums.com/showthread.php?p=3840587


-tg

[Fraps]

Thanks techgnome, I'll see...

And however hard you make it, crackers will find a way around it. So be sure to find a balance and not spend too much time/money on it.

Ok, let's assume random users do not have knowledge to crack the application in some special way instead of simple changing the date in the system. How it looks like from the "ideological point of view" to prevent that?

[baja_yu]

Keep track somewhere of the date and time when application is launched, and also do it periodically from your application. Do it every hour or so. Every time before recording current date/time check the stored values. If the stored is ahead of the current, you'll know that the user reversed the system clock.