In this context (graphic design software) a hardware key is likely to be an enabling device. Sometimes known as a "dongle" this is a device which plugs into the host computer to validate the legitimacy of the software and prevent it being used more than once, since it is required to be present in order for the software. Keys may historically have been parallel (printer port) based but modern devices would use a USB port, in a similar way to a memory stick. In some cases hacking methods may modify distributed software to overcome the necessity, but clearly these are illegal and contrary to the licence conditions from the distributor. Hope this helps
Tim W, August 2008
