To create a globally unique 128 bit ID, use the GenerateGUID function.
Globally unique ID's are calculated from Ethernet addresses, Time and more important parameters. GUID's have become so important in the computer world, where the need for unique numbers is high, that it has been made a Standard in the Windows 95/98,NT API calls. GUID's are much used in medical databases and other sensitive databases, as well as computer components management and so on. The GenerateGUID function is not yet a standard of MacOS.
Windows 2000 and later note:
Under Windows 2000 the GUID's cannot be traced to the generation machine. This was a security change in the Win32 API calls. In MacOS and Windows previous to Windows 2000, the GUID can be traced by the Ethernet address.