JOB SECURITY- How to make a VBA script expire!

[cgmojoco]

Has anyone come up with a method for making a VBA script expire?

I.e. it will only work for a specified time and requires the author of the script to renew it at a given point?

I want to be able to do this to strengthen my position as an independent contrator financially...and copy protect my work from unwanted exploitation

Some ideas:
1-MSG box requesting a pre-defined password to renew the time for the script to work along with contact info for the author

2-Ability to define # of days, months and or years the script will work

3-Ability to define the # of days, months and or years that a MSG box warning of pending expiration will appear

4Ability to define the # of days, months and or years that the renew will extend the use of the script with multiple pre-defined passwords allowing different lengths of time extention! Perhaps an encryption method allows you to in another excel sheet (say the comfort of your own home) generate at will a password that will extend a scripts life for 3 months?! They contact you again, and again you generate a "random" password that will extend the original script

5-Anti-hacking measures, using MS's built in security

This might be a useful way of extracting monies over time, for the use of a script you provide....pre-set

Ideas thoughts, point me to work already done in this area?

Thanks!

 

[Norie]

Excel is not a secure environment.

I can think of at least 2 ways to easily get round Neil's code.

Even passwords for Excel are inefficient.

They can easily be cracked.

 

[tusharm]

As Norie already mentioned, Excel is not a secure environment.

Hopefully, no one will take the one suggestion discussed so far seriously.

Personally, if I had to rent software, it would be a last resort, i.e., software that I simply couldn't do without and software that was essentially a monopoly product.

Anything else that had an expiration capability would simply get trashed. And, yes, that goes for all trial programs that OEMs load on a new machine. The first thing I do when I get a new computer is delete the Norton/Symantec/whatever limited duration products from it.

 

[njimack]

So everyone reading this understands, it is examining the windows time, so a user can simply change it.

Agreed, there is a downside to my code. In my situation this wasn't a problem since it's unlikely that our client would change their system time every day.

Excel is not a secure environment.

I can think of at least 2 ways to easily get round Neil's code.

Even passwords for Excel are inefficient.

All true, but if the VBA project is also password-protected, it would deter most users that I've come across. And the client has already asked me why he can no longer view the code (earlier versions weren't password-protected), so I'm fairly confident that in this case, it will remain secure.