Re: Timelimited software
From: Nils Haeck (n.haeckno_at_spamchello.nl)
Date: Wed, 17 Dec 2003 13:39:45 +0100
You can just check the date of a few files, e.g. the dates of the registry
files (user.dat). This will at least show what the date was before last set
back. By the way, not many people like to change their system date because
it can cause a lot of trouble.
You can also check an online TIME server, but only if your system is online
per default. This however raises questions with "callback home" concerns ->
Your application may get branded as spyware.
Payment: you can provide a link to any online vendor, and once paid, the
user gets a code to type into a box, which extends their subscription for 3
months. You can upload a bunch of codes to the vendor, and you must have a
mechanism in your program to check a code for validity (and check that it
can be used only once). This is not waterproof, esp because users can
exchange codes. If you want to secure it further, you'll probably have to
buid a website where users log in and get an online code after paying,
depending on their hardware hash.
If you want a ready-to-go solution with a lot of options, check out
Hope that helps,
"Ottar Smidesang Holstad" <firstname.lastname@example.org> wrote in message
> Hi, I'm in the planning phase of a small application for businesses. The
> plan is to give away the product for free, but charge a monthly licence
> payable in advance either by quarter year, half year, or full year. It
> be a less than 10MB download, without any required registration, and the
> first 3 months will be free. Now, how do I make the application stop
> after 3 months and on subsequent missing payments? It doesn't need to be
> very hard to crack, as the typical user won't find it worthwhile given
> his/hers knowledge about stuff like that, and given the products low
> The product will come with a database, possibly Firebird, so storing
> information about application runs is not a problem.
> What is the strategy to use for this. Obviously, changing the date in
> windows should not work. I have been thinking about counting the number of
> different dates the application has run on. That, of course, won't work,
> just like that, if the user doesn't use it every day. One would have to
> device a algorithm for guessing how many days it is since last run, based
> dates in windows. Quite error-prone, I would guess. Any ideas?