Marvin Varela wrote:
> There are several ways to do something like this.
>
> First, if the PC's date is anywhere before the last recorded date, terminate
> the trial inmediately, they're obviously tampering with the date.
> Second, If your application has something to do with the internet, check the
> date outside the user's PC using a webservice or something similar.
> Third, you could add an additional variable, for example a number of
> executions, so that even if they keep setting the date right (but they will
> fail some time or another) you can terminate the trial if you detect they
> have executed the application more than the reasonable times they could do
> in 30 days (300 times is unlikely, 3000 is almost impossible for any
> interactive application. You could kindly remind them this is a trial
> version every 300 executions, and terminate it at 3000. Make the reminder
> difficult to ignore, make it last 45 sec. and if they try to close it before
> that time close the application and make them start all over again).
>
> Also, after you have detected any attempt to tamper on your application
> leave a trace so that even if it is uninstalled and re-installed completely
> you'll be able to still tell them the trial is over. Don't make this too
> obvious because they will find it and delete it, make it difficult to find
> and completely out of context so there is no way to relate the trace left
> with your application and also don't leave a trace any place where it could
> be deleted by accident.
>
> Hope thsi helps.
>

"Joe_Black" <JoeBlack@newsgroups.nospam> wrote in message
news:O8B9EHeZFHA.2520@TK2MSFTNGP09.phx.gbl...
> Hi all,
>
> I have an app that users can add plug in modules to, each module gets a
> key supplied by us to activate the module for permanent use, the modules
> however must work for a trial period, say 30 days, to allow the user a
> chance to test that the module is what they want before paying for it.
>
> The problem is, when the module is installed the app records the date it
> was first found and uses that date to give the grace period i.e. for 30
> days a message is given stating how long they have left before this
> module stops functioning. Obviousley the user could change the date on
> their PC after the 30 days to be within the 30 day trial period, is
> there any way I can record the actual date so that if the user does
> change the date the module still knows how many days it has been used for.
>
> Or is there a better way to allow a grace period?
>
> Many thanks
>
> Joe

"Marvin Varela" <mvarela@wagerweb.com> wrote in message
news:%23RI%23mmeZFHA.2664@TK2MSFTNGP15.phx.gbl...
> There are several ways to do something like this.
>
> First, if the PC's date is anywhere before the last recorded date,
> terminate
> the trial inmediately, they're obviously tampering with the date.
> Second, If your application has something to do with the internet, check
> the
> date outside the user's PC using a webservice or something similar.
> Third, you could add an additional variable, for example a number of
> executions, so that even if they keep setting the date right (but they
> will
> fail some time or another) you can terminate the trial if you detect they
> have executed the application more than the reasonable times they could do
> in 30 days (300 times is unlikely, 3000 is almost impossible for any
> interactive application. You could kindly remind them this is a trial
> version every 300 executions, and terminate it at 3000. Make the reminder
> difficult to ignore, make it last 45 sec. and if they try to close it
> before
> that time close the application and make them start all over again).
>
> Also, after you have detected any attempt to tamper on your application
> leave a trace so that even if it is uninstalled and re-installed
> completely
> you'll be able to still tell them the trial is over. Don't make this too
> obvious because they will find it and delete it, make it difficult to find
> and completely out of context so there is no way to relate the trace left
> with your application and also don't leave a trace any place where it
> could
> be deleted by accident.
>
> Hope thsi helps.
>
>
> "Joe_Black" <JoeBlack@newsgroups.nospam> wrote in message
> news:O8B9EHeZFHA.2520@TK2MSFTNGP09.phx.gbl...
>> Hi all,
>>
>> I have an app that users can add plug in modules to, each module gets a
>> key supplied by us to activate the module for permanent use, the modules
>> however must work for a trial period, say 30 days, to allow the user a
>> chance to test that the module is what they want before paying for it.
>>
>> The problem is, when the module is installed the app records the date it
>> was first found and uses that date to give the grace period i.e. for 30
>> days a message is given stating how long they have left before this
>> module stops functioning. Obviousley the user could change the date on
>> their PC after the 30 days to be within the 30 day trial period, is
>> there any way I can record the actual date so that if the user does
>> change the date the module still knows how many days it has been used
>> for.
>>
>> Or is there a better way to allow a grace period?
>>
>> Many thanks
>>
>> Joe
>
>