Secure Boot Apparatus with Segmented Control Paths

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Solution Overview

Problem

Existing secure boot methods, such as those defined by the TCG, are inflexible and do not support optional components, leading to complete system failure if one component fails, and lack detailed recording of individual component states during the boot process, making it difficult to diagnose issues and comply with legal requirements for emergency functionality.

Innovation Solution

A method and system that allows multiple execution sequences for secure boot, records the success or failure of each component, and uses multiple RIM Certificates to support optional components, enabling the device to operate in a reduced functionality mode even if some components are revoked or disabled, with a mechanism to update enabled components without customizing certificates for each device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single control path is used for secure boot, then security verification is simplified, but the system cannot tolerate any component failure and loses adaptability

Engineering Contradiction:
Improveboot process control structureVSAvoidcomponent failure tolerance
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent segments the boot process into multiple independent control paths: a first control path for mandatory components and a second control path for optional components. This segmentation allows the system to verify and boot different sets of components based on their criticality, enabling continued operation even when optional components fail while maintaining security verification for mandatory components.

Inventive Principle:
Principle #1Segmentation

2Use of energy by moving object

If auditing features are made optional, then resource consumption is reduced, but verification fails when the feature is not implemented

Engineering Contradiction:
Improveresource consumptionVSAvoidverification success rate
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies local quality by making the auditing feature configurable at the component level rather than system-wide. The auditing feature can be enabled or disabled independently for different components based on their specific requirements, allowing resource-constrained components to skip auditing while maintaining verification reliability for components that require it.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If updated certificates are sent to all devices, then certificate updates are simplified, but devices with different enabled components receive unnecessary certificates

Engineering Contradiction:
Improvecertificate update processVSAvoiddata transmission efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent implements a universal certificate structure that contains verification data for both mandatory and optional components in a single certificate format. This universal certificate can be applied to any device regardless of which specific components are enabled, eliminating the need for customized certificates while maintaining transmission efficiency by sending only one certificate type to all devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2449499B1Secure boot method and secure boot apparatus
Publication Date: 2014.11.26 PANASONIC HOLDINGS CORP
  • EP2449499B1 patent drawingFigure 1
  • EP2449499B1 patent drawingFigure 2
  • EP2449499B1 patent drawingFigure 3

AI summary

A method to allow a device to boot in a secure fashion, even though some of the components within the secure device's firmware may be not present, not authorised, or not correctly operating.