How to write application that expires after some days

[Struts Dude]

Hi

Does anyone know how to write Java application that expires after some
days
on trial version, say 30 days??

Ideally, tinkering with system date will not stop application from
expiring. Maybe by invalidating the application from starting once
date has been manipulated

Thanks

Struts

 

[Uma Shanker]

Hi

Does anyone know how to write Java application that expires after some
days
on trial version, say 30 days??

Ideally, tinkering with system date will not stop application from
expiring. Maybe by invalidating the application from starting once
date has been manipulated

Thanks

Struts

hi.
1. fix the time and date on which program is used/installed for the
first time.
1.a may be the your program's folder creation time
1.b may be MD5 it and put in special file or location.
2. in your application main() method, check this value and continue
based on your policies.
- 1.a or 1.b etc. or may be even more checks can be done.

 

[alan jeeves]

Hi

Does anyone know how to write Java application that expires after some
days
on trial version, say 30 days??

Ideally, tinkering with system date will not stop application from
expiring. Maybe by invalidating the application from starting once
date has been manipulated

Thanks

Struts

You could implement a web based script that your app calls when it is
installed and then everytime it is started to validate the number of days
its been installed - maybe storing the installed date on the server?

Alan

 

[Tris Orendorff]

(e-mail address removed) (Struts Dude) wrote in

Hi

Does anyone know how to write Java application that expires after some
days
on trial version, say 30 days??

Ideally, tinkering with system date will not stop application from
expiring. Maybe by invalidating the application from starting once
date has been manipulated

Simply pop up a window that says two things:

1) 30 days have expired.
2) Please download a new trial version from our site. We have made some improvements and fixed a few
bugs.
3) After they close this dialog, let your app run normally. If you stop your app from running you will lose a
sale.

Do not attempt any fancy stuff with install dates and clock checking, it will only alienate your potential
customers.


--
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GCS d++ s+:- a+ C+ UL++++ P+ L+ E- W+ N++ o- K++ w+ O+ M !V PS+ PE Y+ PGP t+ !5 X- R- tv--- b++
DI++ D+ G++ e++ h---- r+++ y+++
------END GEEK CODE BLOCK------

 

[David Thielen]

And keep in mind no matter how clever your check is - somewhere you
have a spot in your code that is
If (checkFails())
System.exit();

And all they have to do is eliminate those 2 lines of code...

hi.
1. fix the time and date on which program is used/installed for the
first time.
1.a may be the your program's folder creation time
1.b may be MD5 it and put in special file or location.
2. in your application main() method, check this value and continue
based on your policies.
- 1.a or 1.b etc. or may be even more checks can be done.

david@[email protected]
Windward Reports -- http://www.WindwardReports.com
DefendTek -- http://www.DefendTek.com
Page 2 Stage -- http://www.Page2Stage.com
Enemy Nations -- http://www.EnemyNations.com
me -- http://dave.thielen.com
Barbie Science Fair -- http://www.BarbieScienceFair.info
Hillary Clinton -- http://www.HillaryIn2004.org
(yes I have lots of links)

 

[steve]

Hi

Does anyone know how to write Java application that expires after some
days
on trial version, say 30 days??

Ideally, tinkering with system date will not stop application from
expiring. Maybe by invalidating the application from starting once
date has been manipulated

Thanks

Struts

first of all you need to decide how serious you are on this.
If it is to cover a commercial app, then you need to put a lot more thought
into it. from the time before you write your app.

start by having a function that returns true,- always!!!-
then code so that your app will continue based on "true"
as you code add a call to this function in each(randomly ) of your routines.

1.use the java security manager to protect this routine.
2. overload the java zip package, to "change" the compression system, for
this package.
3. encode the first time this app is run along with some system specific
data.( check for silly dates & times, & always check for negative time)
I.E if the install date claims to be 2032 then it is obviously wrong.

4. finally write the protection code of your routine, and change it so that
it only returns "true" if the app is valid or in date.

what you should have is an app that any hacker will always attack your
package that returns "true/false", as it would be too much work to patch all
the other stuff.

you just need to prevent the package from being replaced/overriden.(security
manager) then put all your thought into that package.
the overloaded zip package , will mess up any decompiler programs, because
they ALL reply on standard zip format.

it's not completely fool proof, but it will dishearten all but the hardest
hackers.

steve