Vehicular digital key system, vehicular digital key management method, vehicular device, and mobile terminal

A vehicular digital key management method executed by:

• a mobile terminal that is an information processing terminal carried by a user;
• a vehicular device that is mounted on and used in a vehicle;
• and
• a server that generates a service key unique to each mobile terminal as key information for using the vehicle, the vehicular digital key management method comprising:
• generating, by the server, a plurality of disposable one-time authentication keys based on the service key of the mobile terminal according to a request from the mobile terminal;
• delivering, by the server, the one-time authentication keys to the mobile terminal with an expiration date;
• receiving, by the mobile terminal, the one-time authentication key from the server;
• storing, by the mobile terminal, the one-time authentication key in a predetermined terminal-side memory;
• periodically replacing, by the mobile terminal, a part or all of the one-time authentication keys stored in the terminal-side memory based on the expiration date of each one-time authentication key;
• specifying, by the vehicular device, any one of the one-time authentication keys held by the mobile terminal by communicating with the server or the mobile terminal;
• and
• determining, by the vehicular device, a validity of the mobile terminal using a specified one-time authentication key.

A vehicular device mounted on and used in a vehicle and configured to communicate with each of a mobile terminal as an information processing terminal carried by an user and a server that generates a service key unique for each mobile terminal as key information for using the vehicle, the vehicular device comprising:

• a vehicle-side memory that stores the service key for each user;
• and
• a vehicle control unit having at least one processor, wherein:
• the vehicle control unit generates a one-time authentication key, which is a disposable authentication key, based on the service key stored in the vehicle-side memory;
• and
• the vehicle control unit determines a validity of the mobile terminal using the one-time authentication key.

A mobile terminal as an information processing terminal carried by an user and configured to communicate with each of a vehicular device mounted and used in a vehicle and a server that generates a service key as key information for using the vehicle, the mobile terminal comprising:

• a terminal-side memory that stores a data of the service key;
• a short-range communication unit that performs short-range wireless communication, which is wireless communication conforming to a predetermined short-range wireless communication standard, with the vehicular device;
• a network connection unit for communicating with the server via the Internet;
• and
• a terminal control unit having at least one processor, wherein
• the terminal control unit transmits an authentication key request signal, for requesting the server to deliver a plurality of one-time authentication keys with expiration dates generated based on the service key at once, to the server under a condition that a connection to the Internet is established;
• the terminal control unit receives the one-time authentication key from the server, and stores the one-time authentication key in the terminal-side memory;
• and
• the terminal control unit replaces a part or all of the one-time authentication keys stored in the terminal-side memory based on the expiration date of each one-time authentication key.