?
Solved

best method to implement a 14 day demo version of a for resale program

Posted on 2003-03-11
9
Medium Priority
?
158 Views
Last Modified: 2010-05-18
Hi,

We have developed a new VB based software program intended for resale and have reach the point of implementing some sort of 14 day demo functionality into it.  

Are there any suggestions regarding how we should determine whether the program's demo 14 days have passed.  A text file or registry key seem too easy to bypass and figure out if someone wants to compare the results of a system snapshot before and after install.  Likewise having the 14 days being based on the system clock, could be bypassed with the reversal of the clock's date.

How should we include demo functionality into the program?  How would those that have developed applications for resale done this?  What would your expert suggestions be?

Thank you for you help.

Paul.
0
Comment
Question by:keepliving
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
9 Comments
 
LVL 2

Expert Comment

by:DanAvni
ID: 8117938
you have a few options
1. registry/file/something like that. as you said it's pretty easy to bypass
2. use PPP which will allow you to do it (but you will have to buy it) http://www.softwarekey.com/. this requires coding of the copy protection but it's very powerfull and easy
3. i think install shield has something like an envelope they put on your exe to time limit it.

i'd go with #2 since it gives you the most control of your software
0
 
LVL 6

Expert Comment

by:marconovaro
ID: 8117979

Here is a free ActiveX control that may help you:

http://www.activelock.com

M
0
 
LVL 1

Expert Comment

by:ophirg
ID: 8118505
Hi.

You can write a binary file and encode the date inside it in a way that you would be the only ones which can read it.

Let's say:
  (m) incidental characters and then an integer marking the Day
  (n) incidental characters and then an integer marking the Month
   .
   .
   .


The file should be there at the beginning marked with 0's for each parameter (Day, Month, Year...)

The application would not run if this file is missing or been changed.

Notice that the bin file should be very big (say 0.5M) so it would be hard to crack it.
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 

Expert Comment

by:SlingBlade
ID: 8121966
I like ophirg's idea, but you should make sure that you write the file nested somewhere with hidden properties and that the uninstall program doesn't remove it and the install program won't overwrite it, otherwise a new install would work right around it.  I would suggest writing several hashes to the registry in addition to this file.  It is also a good idea to include the machine's MAC address if it has one to make sure an updated trial file from one machine won't work on another machine.

*


0
 
LVL 70

Expert Comment

by:Éric Moreau
ID: 8122146
0
 

Author Comment

by:keepliving
ID: 8384522
These options all use the same ideas that I mentioned in my question and said I did not want to use.  Sorry guys but I am going to let this question time out.

If you don't agree, please post and we can solve it.
0
 
LVL 70

Expert Comment

by:Éric Moreau
ID: 8384538
Don't let it time out. Ask the Community support (http://www.experts-exchange.com/Community_Support/) to PAQ it.
0
 

Author Comment

by:keepliving
ID: 8384560
Oh cool, thanks for the suggestion Emoreau.
0
 

Accepted Solution

by:
modulo earned 0 total points
ID: 8387253
PAQ'd and 126 points refunded

modulo

Community Support Moderator
Experts Exchange
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

The debugging module of the VB 6 IDE can be accessed by way of the Debug menu item. That menu item can normally be found in the IDE's main menu line as shown in this picture.   There is also a companion Debug Toolbar that looks like the followin…
This article describes some techniques which will make your VBA or Visual Basic Classic code easier to understand and maintain, whether by you, your replacement, or another Experts-Exchange expert.
Get people started with the process of using Access VBA to control Outlook using automation, Microsoft Access can control other applications. An example is the ability to programmatically talk to Microsoft Outlook. Using automation, an Access applic…
Show developers how to use a criteria form to limit the data that appears on an Access report. It is a common requirement that users can specify the criteria for a report at runtime. The easiest way to accomplish this is using a criteria form that a…
Suggested Courses

777 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question