COMMUNICATION SYSTEM, VEHICLE-MOUNTED TERMINAL, ROADSIDE DEVICE

摘要

There is a need to reduce the certificate verification time in a communication system. A communication system (10) includes a certificate authority (100) for performing authentication, a roadside device (110), a vehicle-mounted terminal (120), a first server (130), and a second server (140). The vehicle-mounted terminal transmits its own position information to the first server. The certificate authority acquires information about a vehicle-mounted terminal highly likely to appear according to place and time from the first server. The certificate authority allows the second server to verify validity of a certificate for a vehicle-mounted terminal acquired from the first server. The certificate authority generates a first list of vehicle-mounted terminals having valid certificates and a second list of vehicle-mounted terminals having invalid certificates according to place and time based on a verification result. The certificate authority transmits the first list and the second list to the roadside device and the vehicle-mounted terminal. The roadside device and the vehicle-mounted terminal verify a certificate using the received first and second lists. Thus, the certificate verification time is reduced.