An automotive vehicle body includes a floor structure, a roof structure and a door opening panel welded to the floor and roof structure. Each of the plurality of light incidenceemission portions 10 includes a waveguide member 11 having a first optical axis L1, and a GRIN lens 12 including a second optical axis L2, and has one end 12a connected to an end portion 11a of the waveguide member 11 and the other end 12b provided with an incidenceemission plane 10a. Then, the last mini time key is created by applying a one-way function to the unit time decryption key.