A lighting device achieves power saving and a moderate illumination brightness distribution without having local dark portions. A method of efficiently providing a location of a contents encryption key according to an embodiment of the present invention includes generating metadata containing information regarding a location of a contents encryption key in a rights object, and setting the generated metadata and the rights object in a portable storage device. The nanomaterial-to-metal alloy surface contacts were enhanced by at least one of fusion, embedment and chemical reaction phenomena under high temperature and ultra high vacuum yielding true nanocomposite at the interface. The first member or chassis may be moveable relative to the second member or mower deck.