Patent ID: 7162455

Claim:
An authentication-data issuing system based on unique time, said authentication-data issuing system including a plurality of computers connected with each other via communication lines with one of said computers set to function as a master computer, said master computer comprising: a unique time generating device including time keeping means for sequentially outputting unit time values at predetermined intervals over a preset time-measuring period that begins at a given start point on a selected date and terminates at a given future end point and accumulating means for sequentially accumulating said unit time values output by said time keeping means so as to constantly measure a changing elapsed time within the time-measuring period; transmitter means for, during communication between said master computer and another of the computers subservient to said master computer, transmitting, from said master computer to the subservient computer, authentication data based on an elapsed time measurement, corresponding to a given time point, indicated by said unique time generating device; and register means for receiving and registering an issuance history of unique authentication data created and issued by said subservient computer imparting additional data, unique to said subservient computer, to the authentication data transmitted by said master computer.