Vehicle security apparatus, security method, and recording medium

A vehicle security apparatus mounted in a vehicle, the vehicle including:

• an electronic control unit (ECU) in which the vehicle security apparatus is provided;
• and a zone ECU that is controlled by the ECU and controls a device mounted in the vehicle, the vehicle security apparatus comprising:
• a primary dynamic authenticator that, when an access request from an access source in the vehicle to an access destination in the vehicle is received, makes a determination as to whether to cause a secondary dynamic authenticator included in the zone ECU connected to the access destination of the access request to execute authorization determination for the access request, based on reliability of an application installed in the access source determined based on at least one of application information regarding the application installed in the access source or a state of the vehicle;
• and
• a connection manager that outputs the access request to the zone ECU connected to the access destination when the determination is made to cause the secondary dynamic authenticator that corresponds to the access destination to execute the authorization determination.