Abstract: Each of the embodiments of the present invention relieves a service provider of the burden of managing personal information. A group administration organization device 10 admits a user device to an authorized group by request and sends authority permission information to the user device 20. The user device 20 holds the authority permission information received from the group administration organization device 10 and, on access, sends authority proof information created from the authority permission information using a group signature scheme to a service provider device 30 as requested by it. The service provider device 30, upon being accessed, requests the authority proof information and verifies the authority proof information received from the user device in accordance with the request on the basis of the group signature scheme. When the verification result indicates validity, the service provider device provides a service.

Abstract: A backlight apparatus includes a point light source, a linear light guide, a plane light guide, and a light shield unit. Rays of light radiated by the point light source travel through the linear light guide and the plane light guide, and are output to an illuminated object. The light shield unit shuts out a leaking fraction of rays of light that travels directly from the point light source to the plane light guide, thereby assuring uniform brightness of the output light.

Abstract: Each embodiment of this invention implements step-by-step and empirical authentication of devices upon digital authentication among a plurality of devices. Each of a plurality of authentication devices of each embodiment can unidirectionally generate a hash value of a low experience rank from a hash value of a high experience rank, and receives a set of high experience rank and hash value in accordance with an experience. Upon receiving a certification request of the experience rank from another authentication device, the authentication device transmits a corresponding hash value to the authentication device as a request source. Upon sending a certification request of an experience rank to another authentication device, the authentication device verifies a hash value obtained from the other authentication device on the basis of a self hash value. In this way, the authentication devices authenticate each other's experience ranks.

Abstract: A backlight apparatus includes a point light source, a linear light guide, a plane light guide, and a light shield unit. Rays of light radiated by the point light source travel through the linear light guide and the plane light guide, and are output to an illuminated object. The light shield unit shuts out a leaking fraction of rays of light that travels directly from the point light source to the plane light guide, thereby assuring uniform brightness of the output light.

Abstract: An object of the present invention is to effectively operate a discharging tube. A voltage raising unit and a discharging unit are disposed in a discharging tube. When a voltage is supplied to the discharging tube, the voltage raising unit raises the voltage to be supplied to the discharging tube. The raised voltage is supplied to the discharging unit. Thus, the discharging unit discharges electricity.

Abstract: An object of the present invention is to effectively operate a discharging tube. A voltage raising unit and a discharging unit are disposed in a discharging tube. When a voltage is supplied to the discharging tube, the voltage raising unit raises the voltage to be supplied to the discharging tube. The raised voltage is supplied to the discharging unit. Thus, the discharging unit discharges electricity.