A system an method for distribution of electronic data over a network infrastructure that includes a client device for operation by a user desiring to receive the electronic data and server that contains the electronic data and offering the electronic data for downloading to the client device via the...http://www.google.de/patents/US7246246?utm_source=gb-gplus-sharePatent US7246246 - System for keying protected electronic data to particular media to prevent unauthorized copying using a compound key
