Ensuring device integrity with PRCR

From raw material processing to component manufacturing, assembly and certification, modern devices pass through numerous stages before entering the market. In fact, studies now indicate that most consumer devices will typically pass through about 8 to 15 distinct supply-chain stages before they reach consumers.

Many experts even expect modern supply chains to reach over 20 stages when all tiers of suppliers are considered. But as these supply chains expand, so too does the potential attack surface; 54% of large organizations now say supply challenges are the biggest barrier to cyber resilience. With this in mind, how can device manufacturers ensure that their hardware hasn’t been tampered with while being passed through so many entities?

Examples of hardware supply-chain attacks

In some cases, manufacturers have not been immune to such risks. One such example of this was the Supermicro hardware supply chain controversy. According to Bloomberg Businessweek, this security incident allegedly involved the insertion of miniature spy chips into server motherboards during manufacturing.

As a result, a device allegedly created a hidden backdoor that allowed unauthorized remote access to systems. For manufacturers, this meant that even trusted manufacturing and simple assembly processes could become vectors for compromize, and become a gateway to serious welfare, financial and reputational damage.

Adversaries can even target elements beyond hardware. For example – as in the case of BlackLotus – attackers can compromise the UEFI boot process and bypass Secure Boot. The bootkit can execute before the operating system loads, enabling persistence and allowing attackers to interfere with security mechanisms such as BitLocker, HVCI and Microsoft Defender.

To prevent such detrimental attacks from happening again, manufacturers are demanding the means to attest that their device comes out of the supply chain the same way it entered; in its original, trusted state. This demand is being met by Platform Requirements for Certificates and RIMs (PRCR).

What is PRCR?

Formerly known as Firmware Integrity Manifest (FIM), PRCR defines how platform suppliers provide both platform certificates and Reference Integrity Manifests (RIMs), so users can easily verify the integrity and composition of their enterprise PC clients and servers.

FIM was superseded to reflect the addition of servers and components beyond the initial specification’s capabilities. Building on FIM’s strong foundations, PRCR determines if a system’s hardware or firmware has been modified while in transit, meaning that if any customizations are made, they should be authentic, visible and traceable.

This is achieved through two well-established TCG standards. Platform Certificates are crucial for identifying the platform’s hardware composition and associated supplier assertions, while RIM describes the expected firmware measurements and compositions of the platform firmware, as well as any relevant components.

Part of this is made possible by the new Component RIM Binding for SWID and CoSwid specification. This defines how to format, store and deliver RIM data which contains the expected component measurements, in order for it to be used by a verifier. This maps abstract RIM information models onto concrete, cryptographically signed files, allowing for the secure validation of components during attestation.

Together, both specifications ensure devices remain in their verifiable, trusted state for their entire lifecycle.

How does PRCR relate to global standards?

The security capabilities PRCR delivers are in line with the requirements described in the National Institute of Standards and Technology (NIST) SP 1800-34, titled ‘Validating the Integrity of Computing Devices’. Designed for the standardization of supplier deliverables – both certificates and manifests – that can be used in device integrity validations workflows, PRCR can be used to support this process.

It can also build on prior work that was aligned with NIST’s initial public draft, more commonly known as SP 800-155. Despite no further updates to technical guidelines published by NIST in October 2024, the document continues to provide a valuable conceptual foundation for approaches to firmware integrity.

As an organization, TCG works very closely with several regulatory frameworks that align with our standards and specifications. PRCR marks the next evolution of the capabilities delivered through FIM, and will continue to deliver hardware and firmware integrity in devices across the globe, in tandem with the latest updates from organizations like NIST.