bcTrialVersion.NET stores information about the trial usage of the software and decides if the software has expired or not when asked programmatically using the IsExpired function.

Information regarding the trial period is kept in Windows registry in either plain or encrypted form.

Users of the component can supply their own encryption algorithms if they want to do so.

The trial version types can be one of the following:

a) Expire in n number of days after first try (or installation if the installer creates the required registry information)
b) Expire on date.
c) Expire after n number of tries.

Read more about bcTrialVersion.NET Component here.