US Patent 11405208 Vehicle communication system and method of security communication therefor

A security communication method of a client ECU included in a vehicle Ethernet network includes transmitting a first message generated based on a first random number generated by the client ECU, first security version information of the client ECU, and a symmetric key pre-shared with a server ECU, to the server ECU, receiving a second message generated based on a second random number generated by the server ECU, second security version information of the server ECU, and the symmetric key in response to the first message, from the server ECU, when successfully verifying the second message, storing the second random number in a memory of the client ECU, transmitting a third message to the server ECU and generating a session key based on the first random number, the second random number, and the symmetric key, and transmitting a fourth message encrypted using the session key to the server ECU.