Abstract: Provided is an electronic key apparatus for a vehicle, capable of suppressing power consumption, reducing a verification time, and improving responsiveness of an on-vehicle device. The electronic key apparatus for a vehicle includes an on-vehicle device and a plurality of portable devices.

Abstract: Provided is an electronic key apparatus for a vehicle, capable of suppressing power consumption, reducing a verification time, and improving responsiveness of an on-vehicle device. The electronic key apparatus for a vehicle includes an on-vehicle device and a plurality of portable devices.

Abstract: An electronic key apparatus for vehicle includes a vehicle mounted device, and a portable device. When the vehicle mounted device communicates with the portable device and verifies an ID code for the portable device, the vehicle mounted device activates a control device mounted on the vehicle. The vehicle mounted device includes a first transmission/reception unit, a first memory that stores ID codes, a first CPU that transmits a request signal to the portable device, and decrypts whether a received answering signal matches the ID code, and a drive unit that outputs a control signal. The portable device includes a second transmission/reception unit, a second memory that stores an inherent ID code, and a second CPU that receives the request signal, encrypts the inherent ID code and transmits as an answering signal. The vehicle mounted device further includes an order changing unit that changes an order of transmitting request signals.

Abstract: A vehicle control system is such that a mobile device transmits a cipher code to an in-vehicle control device based on pre-stored data, and the in-vehicle control device decrypts the received cipher code based on pre-stored data, in order to output a necessary control signal to equipment mounted to a vehicle, the vehicle control system including: the mobile device and the in-vehicle control device each having a memory circuit for storing data for producing cipher related data including a cipher key and an ID code, which are a source of the cipher code; wherein the vehicle control system produces the cipher related data by reading out data in the memory circuits and subjecting the data to a predetermined process determined in advance, and performs production and decryption of the cipher code based on the produced cipher related data.