ONBOARD COMMUNICATION SYSTEM, ONBOARD COMMUNICATION CONTROL DEVICE, ONBOARD COMMUNICATION DEVICE, COMMUNICATION CONTROL METHOD, AND COMMUNICATION METHOD

摘要

Provided are an onboard communication system, onboard communication control device, onboard communication device, communication control method, and communication method, with which a plurality of devices for which different security levels are set can coexist.　With an onboard communication system according to the present embodiment, a plurality of onboard communication devices are classified into a plurality of security levels, and a common key is defined for each of the security levels. The onboard communication devices: store the common keys according to the security levels of said devices; append, to transmitted messages, authentication codes generated using the common keys; and using the common keys, determine the correctness of the authentication codes appended to the received messages. The onboard communication control device: stores the common keys of each of the security levels; using the corresponding common keys, determines the correctness of the authentication codes appended to the received messages; and if the authentication codes are determined to be incorrect, provides a notification to the onboard communication device which does not store the common keys used in the determination.