Secure OS Boot via Health Value Segmentation

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Solution Overview

Problem

Many applications on computing devices are unable to process state inputs from security modules effectively, leading to compromised devices being used inadvertently, allowing malicious control and data theft due to resource constraints and complexity in distinguishing between secure and compromised hardware configurations.

Innovation Solution

A trust module generates device health values based on hardware and software states at boot-up, comparing them to reference values to determine the device's security status, initiating recovery processes if compromised, and using health certificates and keys to ensure secure operation and data protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the security module monitors all hardware components during boot up, then the security monitoring coverage is improved, but the processing complexity and resource requirements increase significantly

Engineering Contradiction:
Improvesecurity monitoring coverageVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the hardware monitoring into two categories: invariant hardware components (core processing units, memory controllers, I/O controllers) and peripheral hardware components (display adapters, audio devices, storage devices). The security module only monitors invariant components to generate health values, while peripheral components are excluded from security verification. This segmentation reduces the number of components requiring security monitoring while maintaining essential security coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts and excludes peripheral hardware components from the security monitoring process. By identifying and removing non-essential components (display adapters, audio devices, storage devices) from the monitoring scope, the system reduces processing complexity while retaining monitoring of critical invariant components that fundamentally affect system security.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If applications process all state inputs from the security module, then the security verification accuracy is improved, but the resource consumption and processing time increase

Engineering Contradiction:
Improvesecurity verification accuracyVSAvoidresource consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential invariant hardware component states from the complete set of security module inputs. Applications receive and process only these filtered health values rather than all possible state inputs, reducing processing resource consumption while maintaining verification accuracy for the critical components that determine system security.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the state inputs into two groups: invariant hardware component states (processed by applications for security verification) and peripheral component states (excluded from application processing). This segmentation allows applications to focus computational resources on verifying only the essential security-critical components.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the system verifies all hardware configurations, then the security assurance is improved, but the boot time and system initialization duration increase

Engineering Contradiction:
Improvesecurity assuranceVSAvoidboot time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments hardware verification into two phases: invariant component verification (performed during boot up to generate health values) and peripheral component verification (excluded or deferred). By limiting boot-time verification to only invariant components, the system maintains security assurance for critical elements while reducing the time penalty associated with comprehensive verification.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary generation of health values for invariant hardware components during the boot process, before full system initialization. This preliminary action establishes a security baseline early in the boot sequence, allowing the system to proceed with application loading without waiting for complete hardware verification, thus reducing overall boot time.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3033710B1Secure os boot as per reference platform manifest and data sealing
Publication Date: 2020.09.23 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3033710B1 patent drawingFigure 1
  • EP3033710B1 patent drawingFigure 2
  • EP3033710B1 patent drawingFigure 3

AI summary

The use of one or more device health values to indicate the health status of a computing device may enable operating system developers to directly manage the security configuration of the computing device. The generation of a device health value involves initializing hardware components of a computing device and loading the operating system according to configuration settings during boot up of the computing device. The device health value is then generated based on a state of the hardware component and/or a state of a software stack that includes the operating system at boot up. The device health value may be compared to a reference health value to determine whether the computing device is in a secured state.