Connected Car Standards – Thank Goodness!

Intelligent transportation systems (ITS) require harmonization among manufacturers to have any chance of succeeding in the real world. No large-scale car manufacturer, multimodal shipper, or MaaS (Mobility as a Service) provider will risk investing in a single-vendor solution. Successful ITS require interoperable components, especially for managing cybersecurity issues. See for a set of reports on ITS cybersecurity.

The good news is we now have a standard for automotive cybersecurity, ISA/SAE 21434. This standard addresses all the major elements of connected car security including V2X, reaching from the internals of ECUs and communications busses including CAN to the broader issues of fleet management and public safety. See for the current draft version of this standard.

Intelligent transport systems rely on complex, contemporary infrastructure elements, including cloud (for data aggregation, traffic analysis, and system-wide recommendations) and 5G (for inter-component networking and real-time sensing). ITS also rely on aging industrial control systems and components, for vehicle detection, weather reporting, and traffic signaling, some dating back forty years or more. This profound heterogeneity makes the cybersecurity problem unwieldy. Automotive systems generally are the most complex public-facing applications of industrial IoT. Any information security problems with them will erode public trust in this important and ultimately critical infrastructure.

Robert Bosch GmbH began working on the first automotive bus architecture in 1986. Automobiles gained increasing electronic functions (smog controls, seat belt monitors, electric window controls, climate controls, and so on). With each new device, the manufacturers had to install additional point-to-point wiring to monitor and control them. This led to increasing complexity, the possibility for error, extended manufacturing time, more costly diagnosis and repair post-sales, and added weight. See Figure 1 for details. By replacing point-to-point wiring with a simple bus, manufacturers could introduce new features connected with one pair of wires for control. This simplified design, manufacturing, diagnosis, and improved quality and maintainability.

Figure 1: CAN Networks Significantly Reduce Wiring (from National Instruments–can–overview.html)

The bus was simple: all devices saw all traffic and responded to messages relevant to them. Each message has a standard format, with a header describing the message content and priority (the arbitration IDs), the body which contains the relevant data, and a cyclic redundancy check (CRC), which is a code to verify that the message contents are accurate. This CRC uses a mathematical formula to determine if any bits have flipped, and for small numbers of errors can correct the message, like a checksum. This is not as powerful as a digital signature. It has no cryptographic power. Every device on the bus can use the CRC algorithm to create a code for messages it sends and to verify the data integrity of messages it receives. Other than this, there is no data confidentiality, authentication, authorization, data integrity, or non-repudiation in CAN bus messages – or any other automotive bus messages. The devices used in cars are generally quite simple, lightweight, and inexpensive: 8-bit processors with little memory on board. Any device connected to the network is trusted. Figure 2 shows the layout of a CAN bus message.

Figure 2: The Standard CAN Frame Format, from National Instruments

Today’s automobiles have more sophisticated devices on board. The types of messages and the services the offer are becoming more complex. In-vehicle infotainment (IVI) systems provide maps, music, Bluetooth connectivity for smartphones and other devices, in addition to increasingly more elaborate driving assistance and monitoring systems all add more traffic to the bus. But given the diversity of manufacturers and suppliers, impeding security measures over the automotive network. No single vendor could today achieve what Robert Bosch did nearly forty years ago. Yet the need for stronger vehicle security is growing.

The ISO/SAE 21434 standard describes a model for securing the supply chain for automotive technology, for validating the integrity of the development process, detecting vulnerabilities and cybersecurity attacks in automotive systems, and managing the deployment of fixes as needed. It is comprehensive. ISO/SAE 21434 builds on decades of work in information security. By applying that body of knowledge to the automotive case, the standard will move the industry towards a safer and more trustworthy connected car world.

But the standard’s value doesn’t stop with cars and intelligent transport systems. Domains far beyond connected cars will benefit from having a model for securing communications among elements from diverse manufacturers sharing a common bus. The CAN bus and related technologies are used onboard ships, in aircraft, in railroad management, in maritime port systems, and even in controlling prosthetic limbs. The vulnerabilities are common, the complexity of the supply chain is equivalent, and the need for a comprehensive architectural solution is as great. So this standard is a superb achievement and will go far to improve the quality, reliability, and trustworthiness of critical systems globally.

What do you think? Let me know in the comments below or @WilliamMalikTM.

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