Secure Controller Area Network (CAN) Transceiver With Embedded Authentication Support

The growing number of security threats and vulnerabilities in automotive and industrial control systems motivates the design of Controller Area Network (CAN) bus components with enhanced security measures while maintaining compatibility with existing standards and allowing for interoperability with non-enhanced systems. We present such an enhancement that is implemented by replacing standard CAN bus transceivers with a new transceiver that permits automatic authentication of CAN frames. The theoretical basis of our approach is based on incorporating a secondary communications channel in a virtual manner that simultaneously transmits an authentication signature with each CAN frame. To implement the authentication mechanism, a new backward-compatible transceiver is described, designed and validated that implements the virtual channel through selectively delaying the rising edges in a Non-Return-to-Zero (NRZ) waveform that encodes a CAN frame at the physical layer. Novel aspects of the CAN transceiver include the use of use of authentication signature generators and comparators, rising edge time-based modulator/demodulator circuitry, and phase-preserving rail converters. The mixed-signal transceiver circuit was fabricated using a $0.18\mu $ m CMOS process and operation was validated over PVT corner cases and with non-secure transceivers to demonstrate backward compatibility.