I am in the process of exploring the software protection schemes for my company. Sure enough, there are so many alternatives and almost all of them give a facility to limit:
Now if I think about it, there must be some place in computer where "number of times the application has been used" or "number of days it has been used for" is stored. Here I assume that an application protected using one of these mechanism would NOT require it to run with Administrative privileges. And I understand that an application with normal user rights cannot modify a place which affects other users. Which would mean that if an application is expired for user A, it will still run for user B (which looks foolish enough). I wonder what place these schemes can possibly hide their information in to make it work?
I know some protection mechanisms that require to be run with administrative privileges at least once (e.g. during installation). I assume they set up a place in a non-user-specific location (e.g. under HKEY_LOCAL_MACHINE or ProgramFiles or even WinDir) and also set write permissions for (authenticated) users to that location.