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Trail Code

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allanmc10

Programmer
Feb 23, 2006
39
GB
Hello fellow programmers

I am hoping you can help i am looking for Vb.net app to have a 30 day trail. Is their any 1 that can point me in the roght direction on help with some code for 30 day trail

Cheers

Big Al
 
How secure must this be?

Chip H.


____________________________________________________________________
If you want to get the best response to a question, please read FAQ222-2244 first
 
You could use the installation date using:

1) A hidden reg key
2) A file stored in the apps folder
3) A file installed with the app, write to it during the installation, and check FileInfo.LastWriteTime every time the app starts

There are lots of different ways, but as chiph says, how secure do you need it?


 
Very secure, but not to sure how to go about this

regards

big al
 
Got to be a reg key really but not put anywhere obvious.

You obviously need to avoid users being able to re-install the app on day 29 and then carrying on with another 30 days.

If when you start your app the key is not there you create it and enter the current date. If the key is there do a date diff between now and the key date and crap out if >= 30 days.
 
You could use all three that i suggested, it would keep people guessing.
If you also add a file to the Win directory and using the date modified, it would allow you to check if the app was installed before. I would do all of the steps when the application is first run, because ms installer may pick them up, and when the user uninstalls the app, it could also remove these files/reg keys.
 
'because ms installer may pick them up, and when the user uninstalls the app, it could also remove these files/reg keys.'

Only if you include these files in the MSI. The reg key should be added in code and not at the install stage.
 
I suppose it would depend on the value of your application but may I suggest the KEY-LOK II from MAI Digital Security.

For only a few pounds you can secure your application and do a lot more to boot, you can even extend your evaluation period, enable / disable features etc., and if like us, you have several applications these can all be secured with a single dongle. Well worth a look at.


HTH

P.S. I've no affiliation with this company it's just that we use it and have no hesitation in recommending it.
 
Suggestion:
Don't rely on only one technique to secure your app. It will get cracked, and when it does (look for your app name on the cracker message boards), you'll need to change your technique to stay ahead of them.

Chip H.


____________________________________________________________________
If you want to get the best response to a question, please read FAQ222-2244 first
 
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