Abstract: A method and apparatus for protecting digital content stored in a universal serial bus (USB) mass storage (UMS) device from unlimited distribution are provided. According to the method and apparatus, a UMS device generates a random key according to a request from a user and shows the generated random key to the user, and then, by using the random key, registration data is encrypted. Accordingly, only a USB host that registers the UMS device after the user connects the USB host directly to the UMS device, can freely use digital content of the UMS device, and even if encrypted registration data of the UMS is leaked out, unauthorized devices cannot register the UMS device.

Abstract: An information recording medium, in which a software version of an apparatus for reproducing contents is actively examined in order to provide update information about the software used in reproducing contents, the apparatus for reproducing contents, and a method of reproducing contents. The information recording medium includes contents and an active application which checks a version of software of an apparatus for reproducing the content and provides update information based on the checked version.

Abstract: Disclosed is a portable signal light. The portable signal light comprises a signal light section and a self-generator. The signal light section has a hollow signal light body to an inner surface of which a light emitting sheet is attached, a vertically positioned panel which is located inside the hollow signal light body, a plurality of LED elements which are fastened to the vertically positioned panel to be spaced apart one from another by a predetermined distance, and an illuminating lamp which is integrally secured to the hollow signal light body. The self-generator functions to generate power to be fed as operating power to the LED elements of the signal light section, the illuminating lamp and an external load.