DBCSec: DBC File-Guided Secure Communication Mechanism for CAN-FD Bus

The network architecture of modern vehicles is composed of multiple communication protocols and electronic control units (ECU). Compared to the widely used protocol of Controller Area Network (CAN), CAN with Flexible Data-Rate (CAN-FD) protocol is suitable for applications requiring higher data throughput. However, the CAN-FD bus is vulnerable to intrusion by external attackers. Nowadays, several secure mechanisms have been proposed to protect the security of in-vehicle data. However, there are still two issues: 1) Most schemes use a centralized controller for key distribution, which can easily lead to a single point of failure; 2) The existing key management modes are not suitable for real-world CAN-FD networks in vehicle manufacturing. To address these issues, we propose a lightweight semi-decentralized scheme based on Database CAN (DBC) files to secure in-vehicle communication. ECUs are grouped on the send-receive relationships set in the DBC file, considering both the communication mode and sending efficiency. Furthermore, the proposed scheme overcomes reliance on long-term keys. Moreover, the security is analyzed by the random oracle model. The performance analysis is evaluated on microcontroller units (MCU) STM32H743IIT and Raspberry Pi 3B. The proposed scheme optimizes the computational costs of authentication, key agreement, and secure communication stages by up to 97.89%, 99.95%, and 82.35%, and optimizes the communication costs by up to 75.52%, 98.42%, and 29.41% compared to existing methods. Simulation experiments demonstrate that the bus load of the scheme increases by up to 9.84% compared to the baseline network.