Secure Boot Hardware Root of Trust for DRM Integrity

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Solution Overview

Problem

Existing systems lack effective methods to establish trust between client devices and servers while ensuring the integrity and authenticity of media playback, particularly in securing digital rights management and preventing reverse engineering of applications.

Innovation Solution

A secure boot process is implemented on client devices, utilizing secret values burnt into hardware to verify the integrity of the operating system and applications, which then establishes trust with a server through a special API, and employs obfuscation techniques to harden the DRM system against reverse engineering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If secure boot process is implemented to verify operating system and application integrity, then trust establishment between client device and server is improved, but device complexity increases

Engineering Contradiction:
Improvetrust establishmentVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements secure boot process that performs verification actions before the operating system and applications are executed. Secret values are burnt into hardware during manufacturing, and the boot loader verifies the integrity of subsequent components (OS, applications) before loading them. This preliminary verification ensures trust is established before any potentially untrusted code runs, resolving the contradiction by performing security checks in advance rather than adding complex verification during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a boot loader as an intermediary component between the hardware and the operating system. The boot loader contains a verification module that uses secret values stored in hardware to verify the integrity of the OS and applications. This intermediary layer simplifies the overall system architecture by centralizing the verification logic in a dedicated component rather than distributing complexity across multiple subsystems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If applications are hardened against reverse engineering through obfuscation techniques, then security against reverse engineering is improved, but ease of manufacture and deployment worsens

Engineering Contradiction:
Improvesecurity against reverse engineeringVSAvoidease of deployment
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies code obfuscation techniques that transform the application's code structure by changing parameters such as variable names, control flow, and data representations. The verification module in the boot loader is configured to accept obfuscated code as input, and the obfuscation level can be adjusted by modifying configuration parameters. This allows the same deployment process to handle both obfuscated and non-obfuscated applications, maintaining ease of deployment while improving security.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If secret values are burnt into hardware during manufacturing, then integrity verification capability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveintegrity verification capabilityVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent implements a self-service approach where the client device automatically generates and stores its own secret values in hardware during the manufacturing process. The verification module uses these self-generated secret values to verify the integrity of the operating system and applications. This eliminates the need for external authorities or complex centralized key management systems, simplifying the overall manufacturing process while maintaining strong integrity verification capabilities.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3025226B1Media client device authentication using hardware root of trust
Publication Date: 2019.12.04 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3025226B1 patent drawingFigure 1~2
  • EP3025226B1 patent drawingFigure 3
  • EP3025226B1 patent drawingFigure 4

AI summary

A client device for media playback includes a user-installable media client application which implements the client-side of a digital rights management (DRM) system. The client device employs secure boot and verifies the user-installed application. The application is hardened against reverse engineering, and it utilizes a special API provided by the client device to tie into the secure boot, bridging the gap between the secure boot and the client-side of the DRM system contained within the application.