Need help creating machine time independent license

See more:

C#

ASP.NET4

WCFServices

Hello,

I have a WCF service which i need to deploy on client server for some trial period as per his buy period, and i have done date encryption in database and would be checked by a method ExpireDate < TodaysDate.

But the issue is client can change his system date and use this service. Is there any way/solution by which this logic of Licensing can be implemented independent of Machine time.

If you have any links for licensing of wcf service independent of Machine Time, pls guide.

Thank you.

-K15