CAN-MM: Multiplexed Message Authentication Code for Controller Area Network message authentication in road vehicles

TL;DR

This paper introduces CAN-MM, a novel multiplexed MAC scheme for CAN networks in vehicles, enabling secure message authentication without protocol modifications and supporting all CAN versions.

Contribution

CAN-MM utilizes frequency modulation to multiplex MAC data with CAN messages, ensuring backward compatibility and simultaneous data and MAC transmission.

Findings

Supports all CAN protocol versions

Enables simultaneous data and MAC transmission

Maintains full backward compatibility

Abstract

The automotive market is increasingly profitable for cyberattacks with the constant shift toward fully interconnected vehicles. Electronic Control Units (ECUs) installed on cars often operate in a critical and hostile environment. Hence, both carmakers and governments have decided to support a series of initiatives to mitigate risks and threats belonging to the automotive domain. The Controller Area Network (CAN) is the primary communication protocol in the automotive field, and the integrity of the communication over this network is assured through Message Authentication Codes (MAC). However, limitations in throughput and frame size limit the application of this technique to specific versions of the CAN protocol, leaving several vehicles still unprotected. This paper presents CAN Multiplexed MAC (CAN-MM), a new approach exploiting frequency modulation to multiplex MAC data with standard CAN communication. CAN-MM allows transmitting MAC payloads maintaining full-back compatibility with all versions of the standard CAN protocol. Moreover, multiplexing allows sending DATA and MAC simultaneously.