'cpuid' output and software licensing question

[alishapal]

Hi
I am trying to use 'cpuid' instruction to get a unique number so I can use it for generating a license number for my application. I would like to know if it is possible to do such a thing with CPU id or I have to use some other methods like MAC address of a NIC card ?
I have read articles on the net about possibilty of using cpu id, but on the other hand some say that since it has privacy issues, Intel has dropeed embedding an id on its cpus
Any help regarding this matter is highly appreciated
Thanks
Hamid

[TimP]

According to the Developers' Guide, EM64T continues to support processor serial number. I suppose one of the reasons for applications to continue to use NIC address is that it's simpler for multiple CPU's, and doesn't involve as much testing on various conceivable customer configurations.

[alishapal]

But MAC address can be easily changed or user can fake one...

I am still not sure if result of cpuid instruction is usable for this purpose ? I intend to require users of my application have at least Pentium processor so I think I can skip some of the tests

Thanks

Hamid