Creating an evaluation version or trial version

Hi,

Can some one please suggest a simple effective and probably platform independent way by which I can create a trial version of an application?

1. The trial version is full featured software, that can be used for either 30 or 60 days.
2. After the trial period, the user should enter the license key in order to use it.
3. When user enters the license key, application should know if the key entered is right or wrong.

I think the way Qt does it is nice (but I have no idea about the internals).

Thanks for suggestions.

I doubt there is any platform independent solution. I think you should look for platform specific ones.

Can you please suggest some windows specific solutions ?

Thanks a lot.

Did you find a solution for the problem, i've also the same problem but no solution.

If you have one, can you please share the solution with me.

Best Regards
NoRulez

any findings?

This is what I did many years ago:
The first time, when the application loads, I write the current time to a registry key.
After that, every time the application loads I check the time in that registry and compare it to the current time, if the delta time is longer than the demo version limit, the application returns without loading the main user interface... I just show a window that says 'demo version finished'.

Quote:

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Originally Posted by pixaeiro

This is what I did many years ago:
The first time, when the application loads, I write the current time to a registry key.
After that, every time the application loads I check the time in that registry and compare it to the current time, if the delta time is longer than the demo version limit, the application returns without loading the main user interface... I just show a window that says 'demo version finished'.

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I think this very simple. Anyone have another method?

They are all going to be variations on this theme where the method of storing an expiry date changes

Yes, and the sad fact is that you can find crackz for products like Photoshop, Maya, 3dsmax, Houdini, Nuke, etc, etc, etc... These products have authorization libraries that were very expensive to be developed, but still crackers crack them.
You just need to make it a little inconvenient for your users to go past beyond their trial period... But I wouldn't suggest spending a lot of time on this... Better to spend it on new functional code or bug fixing!

Form many years shareware, crippleware, or breakware were all the rage. To truly have a 30 60 90 use life you must get creative. Use a 'Matryoshka' file. Take one of the files in the install, the eula file for example;

Quote:

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END-USER LICENSE AGREEMENT FOR THIS SOFTWARE
Important - read carefully:

This End-User License Agreement ("EULA") is a legal agreement
between you (either an individual or a single entity) and the
mentioned author of this software for the software product
identified above, which includes computer software and may
include associated media, printed materials, and "online"
or electronic documentation ("SOFTWARE PRODUCT").
By installing, copying, or otherwise using the SOFTWARE PRODUCT,
you agree to be bound by the terms of this EULA. If you do not
agree to the terms of this EULA, do not install or use the
SOFTWARE PRODUCT.

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Inside, take several lines and count spaces. Extra spaces are typos and one or two here or there no biggie. Do a check before you launch your app, if the file is missing or the space count is wrong, Dialog an error/warning and close. If the count is correct, use the file mod date to get your count to REGISTER date. When they register/pay send a small patch to overwrite the 'Matryoshka' file with a corrected one. No extra files, no registry edits, just a correction for typos. You can leave the scan code in place if you want, as all future counts will be correct. This is old data and should be treated as such.