Integrating Licensing into a VFP application 1

[Rajesh Karunakaran]

Dear all,

I want to integrate an appropriate licensing feature to our VFP application. The license need to be modules-wise or a group of modules wise. This means that there need to be different licensing options under which different set of modules shall be included (means sold).
For example, Payroll option is optional and not included with the general modules.

What are your suggestions? Is there any open-source solution for VFP which offers this feature?

Thank you all in advance,
Rajesh

 

[Mike Gagnon]

Use and ini file that would contain an encrypted string listing the modules purchased.
On startup decrypt the string and keep into memory and make your icons appear of disappear depending of the module purchased.

Mike Gagnon

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[Mike Lewis]

Personally, I wouldn't bother to look for "an open source solution". It would be much easier just to code it yourself. All you need is a set of some sort of codes or flags, stored somewhere that's not obvious to the user. The flags would simply indicate whether or not the current user has permission to use the module. And possibly incorporating an expiry date.

My choice would be to store the flags in the Registry - but not under the name of your company or application. Alternatively, use an INI file (as per Mike G's suggestion) or even a simple text file. Place it in a hidden file or hidden directory, or give it a name that won't tell the user what it is.

Given that you have developed a payroll module, and presumably others, you should find this easy enough.

Mike





__________________________________
Mike Lewis (Edinburgh, Scotland)

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[Rajesh Karunakaran]

Dear Mike G and Mike L,

Thank you very much for your views. However, it is not only about showing only the selected modules to the user. In fact, I am looking for a licensing method for the full application. That means, there should be a License Key or something like that without which, in a pre-defined format, the software wouldn't run. But, in that case also, how to prevent multiple copies misusing the same key.

Please advice me of methods that are familiar or popular.

Thanks,
Rajesh

 

[Olaf Doschke]

Like I suggested on several occasions, use something from a company specialized on that topic. When you want to be serious, especially about the inability to simply copy all software including the key, something using a hardware dongle. I think I somewhere pointed to

https://www.wibu.com/wibukey.html,

I have no association with them and I don't say they are the only or best company, but it illustrates what I mean.
It's viable to use such hardware related protection for a software you would like to sell for some hundreds or even a few thousand dollars.

You also always and still find people binding their software to a specific pc by verifying hardware serial numbers. That has its problems if hardware is changed and the license still is valid, you can then only either trust customers saying the move to new hardware and suspect customers moving each month, but whatever your trust level is, such protection is always having the extra work of customers needing new keys when hardware changes and such a dongle instead is reusable.

Of course, there also are downsides, if every software would be protected that way computers would need so many dongles attached, that free ports become rare or you would need to change dongle every time you start some software, that's not practical, but it is for such an important package like an ERP system. Even as a private person my mother, for example, owns an expensive multimedia video software protected by such a dongle system.

Ideal systems need no obfuscations, users can know what protects your software and still not crack it and the best thing obviously is some hardware, because that is not something easy to copy, in the ideal case at least it's not just any USB key with a certain software installed, that indeed could also be copied.

If you want something simply just software based go the serial number route, you find routines getting that.

Bye, Olaf.

 

[GriffMG]

Have you thought of an online solution, where you application queries a web site to find what has been licenced?

So when it's installed it generates a unique key locally and hides it as Mike says, then each time it is run it queries your web site with that
key and gets a list of allowed modules.

You could use a GUID, plus perhaps the serial number of the processor, for the unique key and obfuscate the conversation with your web site to prevent abuse.

If a user got a new PC you could issue a new key and cancel the old one on your server.

Regards

Griff
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[Rajesh Karunakaran]

Dear all,

Thank you very much for your time.
Let me check the options.

Rajesh

 

[TamarGranor]

You might find some useful ideas in this paper:

http://doughennig.com/papers/Pub/Jun00.pdf

Tamar

 

[Rajesh Karunakaran]

Thank you Tamar.
I will check that.

Rajesh