Building Secure Cars

3Automotive‐Grade Secure Hardware

TRUST IS BUILT ON LAYERS STARTING WITH A FIRST LAYER

This chapter provides a brief introduction to automotive‐grade secure hardware, specifically automotive hardware security modules (HSMs). Although the main focus of this book is on secure software development for the automotive industry, the overall security of a vehicle or automotive system relies not only on secure software but also on the security of the underlying hardware. Therefore, we will briefly discuss automotive HSMs and how it is possible to build secure software on top of secure hardware.

The automotive industry has experienced several cases of software‐based attacks on vehicles, which highlights the need for automotive HSMs. A couple of examples are presented as follows to provide some insight into the challenges. The UDS (Unified Diagnostic Services) Security Access [1] function is typically used for providing authentication of a diagnostic tester against an ECU (electronic control unit) to enable certain diagnostics operations. A simple example of the authentication sequence is illustrated in Figure 3.1 to show the messages involved.

Figure 3.1 Example sequence of exchanged messages for UDS Security Access authentication. Source: Based on [1].

As shown in the figure, the diagnostic tester first sends a seed request message ( 0x27 0x01 ) to the target ECU. The target ECU ...