Hello to everyone,

I have some questions about possible resources that could be used to
develop firefox extensions. I will describe what I need to do, and
would be pleased to know if it's possible or not, or if I'm going the
right way.

The problem

A client that works with payment cards for pharmacies wants to get rid
of his current system and move to a web solution. This system is very
hard to do any maintainence on it (a software installed in pharmacies
that communicates with the central server in a safe way). The problem
is that the central server requires not only the login and password, it
also obligedly requires the machine's id to access it. This way a
certain login and password can only be accessed from a certain machine.
You must have already imagined that my problem is identifying the
client's machine.

The Solution thought

For the server I will use PHP and on client computers will be used the
Firefox browser on a windows operational system.
My means are to create a firefox extension that can identify the
machines settings(for example a mac address if it has a network card, a
serial number of the hard drive, etc.) and use those charateristics so
the server can identify the machine(I know I'll have to use some kind of
hash to guarantee some security)

From what I read in the mozilla documents, the resources I require will
work only if I create an extension using C++ with XPCOM. I started
reading a book called "Creating XPCOM Components" by Doug Turner & Ian

Am I right? Could it be done this way?
Does anyone have any tips, suggestions or something already created of
the same genre?