ELECTRONIC KEY MANAGEMENT SYSTEM ASSISTING DEVICE, ELECTRONIC KEY MANAGEMENT SYSTEM, METHOD, AND STORAGE MEDIUM

An electronic key management system assisting device including: a connector () that is mounted in a vehicle and is used for a connection with an in-vehicle authentication device communicating with a management server using an in-vehicle communication device; and a requester (B) that requests the management server to transmit an execution key for obtaining a permission for a transition to a registration mode in which an electronic key of the vehicle is registered in the in-vehicle registration device or an invalidation mode in which the electronic key registered in the in-vehicle registration device is invalidated using a communication device other than the in-vehicle communication device in a case which the in-vehicle authentication device connected through the connector is not able to communicate with the management server using the in-vehicle communication device.