A system including a plug device, configured to be reversibly operationally plugged into a socket of a standard configuration, and a socket device, configured with at least one restriction structure that prevents a plug that is configured according to the standard configuration from being operationally plugged into the socket device. The plug device is configured with a respective accommodating structure to be reversibly operationally plugged into the socket device despite the restriction structure. The scope of the invention also includes a method of digital rights management by configuring a media player with the socket device of the present invention to connect to a media carrier configured with the plug device of the present invention, thereby allowing only the media carrier configured with the plug of the present invention to download data to this media player.