How to restrict my application to run n number of days.

[Baji]

I am trying to write Licence manager using LabVIEW .I want to restrict my application to run n number of days.My problem is how to do restrict the user if he changed the data and time of the PC.

[MikeS81]

Hi Baji,

there are different possibilities with different complexity. In your case you can store to the starting date, also the current date. If somone change it back you can check it, because it lies behind the last current date.

Mike

[Baji]

Thanks for the quick reply, can u tell me what are the different possibilities with different complexity.

Take this case. I installed the application a month before and I launching the application after a month with manually changing my date to previous month.

I restricted my application by time i have no problems in that.

Message Edited by Baji on 06-24-2009 04:54 PM

[MikeS81]

Hi Baji,

you can use a dongle or an external server to unlock your program.

I think your described case is ok, because then then person never used it. So why would you block a software which is only istalled but never started? I think it's ok if the time starts running with the first start of your program.

Mike

[Baji]

He can daily run the application with modifying the system date to the application installed date,so he gets infinity days validity. by restricting the time he can run software for limited period but depends on it expired how frequently he using.

my aim is to locks the software if n number of days completed.without any dongles or external servers. Ideas are appreciated.

[Coq_Rouge]

In my opinioun a dongle is the best solution. If the software is popular enough somebody will crack it anyway, even with dongle. Examples are Microsoft software and Labview, and almost all CAD/ECAD software. And if you restrict it to sa 30 days. It is not so hard to go around this, if the user choose to be dishonest  

[Baji]

By using dongles can i restrict my application to n Number of days?,even if i changed my system date manually.

[MikeS81]

Hi Baji,

not if you use two buffers. One for the installation date and one for the last used date+time(inkl. seconds). At every start you check if the current date lies behind the last used date+time.

But as Coq rouge already said, you can't make it unbreakable.

Mike

Message Edited by MikeS81 on 06-24-2009 01:49 PM

[Coq_Rouge]

How about a smartcard? This could open for some fancy license management. It is perhaps also cheaper than a dongle

[Baji · Accepted solution]

Thanks Guys.

From the above conversations i am concluding that,

1)We cannot strictly restrict the user for n number of days.

2)Dongles and Smartcards are usefull for effective Licence mangement.