[thelist] Need to add a serial number system to my ASP script.

Craig cd-ml at aardvark.net.au
Sun Sep 12 21:15:19 CDT 2004

Hi Ken,

> How are you licencing the code? Per site? Per server? Can the user
> transfer the licence/software between physical boxes (provided they
> don't use more than the numbfer of copies they bought?)

I'm not sure really. I was going to give the user the .DLL file(s) and
supply them with a serial number that takes the DLL out of "demo mode".

> For example, if the code is licenced per physical server (irrespective
> of the number of processors), and the code can be moved between boxes
> (eg the user upgrades/replaces the box) then I would:
> a) use assymetric key encryption
> b) have the user tell you what the IP address of the server is
> c) create an encrypted config file. The message is the IP address, and
> key is yourp private key. You give this config file to your user.
> d) you embed the public key into your application. When the component
> initialises, it reads in the config file, decrypts it using the public
> key, and checks the IP address against the IP address the machine is
> using.
> This may present issues in a load balanced environment, and isn't
> circumventable by clever programmers, but it's a common technique that
> works for most cases.

At the moment, I think that I won't restrict it by IP address or anything.

Regarding the serial number, how would I actually implement this? I have VB
code here that generates a serial number.  What I'm not sure about is when I
generate a serial number, does it have to decrypt to a certain value, like
the string "password".  So in my DLL I would decrypt the serial number and
if the value is "password" I allow the DLL to run.

Sorry that my explanation is a little vague.

Craig Dyer

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