Cover story
Upgrade platform firmware resiliency with Root of Trust controllers
By Brandon Weekly, Marketing Engineer, Microchip Technology F
irmware is present in many everyday devices, vital to a platform’s ability to run properly. It’s what allows a system to
boot, run operating system updates and even be responsible for hardware components like the power supply unit. Used in everything from data servers
to self-driving cars, personal computers and cell phones, it has become the target of attacks by hackers. Developers have responded with security solutions so firmware is more resilient.
The axioms of secure boot controllers There are certain axioms or points that define the goals of our secure boot controllers, or Root of Trust (RoT) controllers. Our first axiom is immutable
hardware root of trust, which means that every firmware image is authenticated whenever the system
boots or restarts. This is done through hardware, not software, so it can happen before any part of system boot-up and before any operating system or boot firmware is even running. The microcontroller is the very first thing to boot up in the system and has processes that will verify the firmware and hold the host processor in reset, ensuring it cannot do anything until the entire boot process has been verified. The second axiom is hardware- based code authentication, which uses private-public key pairs to sign and authenticate code images. Thirdly, we have secure firmware
updates, allowing future versions of firmware to be installed securely and provide the same protection. Microchip’s root of trust solution is
NIST 800-193 compliant, NIST being the National Institute of Standards and Technology. This standard indicates a
platform’s ability to protect, detect and recover. The solutions protect against malware attacks and detect any attack that might be in progress. For example, should a data image be compromised or corrupted, it is recoverable to a previous good image and the boot can still be successful. There are also a wealth of encryption
algorithms to choose from which are certified by the cryptographic algorithm validation programme. The entire process is very fast, seamless and barely noticeable. A code image verification, in general, will only add a few hundred milliseconds to boot time.
Secure boot process The diagram below shows how an application processor uses the CEC1712 to verify its boot code. The code that we want to run is
stored in SPI flash that is external to the application processor. Two
06 June 2023
www.electronicsworld.co.ukw
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