Root of Trust Chain Validation for Boot Integrity
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Solution Overview
Problem
Current information handling systems lack a mechanism to verify the validity of the chain of trust sequence during the boot process, making them vulnerable to attacks where malicious code can skip firmware volumes, breaking the chain of trust and compromising security.
Innovation Solution
An interlock system is implemented between entities in the boot process sequence, where each entity authenticates the transition process, and a root of trust validates the order of entities against a predefined chain of trust, using an Authenticated EC Interface (AEI) for secure communication and an authorized chain of trust database to ensure legitimate transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional boot sequence is used without chain of trust verification, then the boot process is simple and fast, but the system is vulnerable to malicious code skipping firmware volumes and breaking the chain of trust
Solution Approach 1:
The patent implements preliminary action by pre-establishing an authorized chain of trust sequence that defines the expected order of firmware volumes before the boot process executes. The root of trust stores this predefined sequence, and each firmware volume is verified against it during boot, preventing skipping or reordering of volumes without requiring complex runtime verification mechanisms.
Solution Approach 2:
The patent introduces an intermediary mechanism through the root of trust, which acts as a mediator between the boot process and the firmware volumes. The root of trust verifies each firmware volume's identity and position in the chain using cryptographic signatures and the authorized sequence, enabling secure validation without requiring direct complex interactions between all boot components.
2Reliability
If each firmware volume is verified against a predefined chain of trust sequence, then the security against malicious code is improved, but the boot process time increases
Solution Approach 1:
The authorized chain of trust sequence is pre-computed and stored in the root of trust before the boot process begins. This preliminary preparation eliminates the need for complex cryptographic verification of the entire boot sequence during runtime, as the expected order is already established, reducing verification time while maintaining security.
Solution Approach 2:
The patent replaces complex runtime cryptographic verification mechanisms with a simpler comparison against a pre-stored authorized sequence. Instead of performing full cryptographic validation at each boot step, the system uses the pre-established sequence as a reference, substituting complex mechanical verification with faster sequence matching while maintaining security integrity.
3Reliability
If an interlock system with root of trust validation is implemented, then the chain of trust sequence is protected against alterations, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the boot process into discrete, verifiable steps where each firmware volume is individually validated against the authorized sequence. The root of trust maintains a segmented view of the expected chain, and each verification step is independent, making the complex security function manageable and implementable without requiring a monolithic complex system.
Solution Approach 2:
The root of trust serves as an intermediary that centralizes the complexity of chain verification. Rather than requiring each firmware volume to perform complex verification of the entire chain, the root of trust acts as a mediator that provides authentication services, simplifying the overall system architecture while maintaining strong security against sequence alterations.
Data Source
AI summary
A system for protecting an information handling system from alterations in chain sequencing uses a root of trust to secure transition points between entities in a sequence according to a chain of trust stored in a chain of trust database. Before transitioning control from a first entity transferring control to a second entity receiving control, the root of trust validates the transferring entity and the receiving entity. Failure to validate both entities results in the root of trust stopping the boot process to prevent malicious code from interfering with the BIOS executing the correct steps in the process.