Secure Boot Loader Verifying Firmware Encryption Signatures

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Solution Overview

Problem

In secure boot modes of computer apparatus, firmware applications with powerful functions often struggle to obtain valid digital signatures, leading to security issues and inability to execute, especially for code interpreters like Python interpreters, which can compromise system security even if verified.

Innovation Solution

A method involving a computer apparatus with a firmware volume and boot loader, where the firmware application module is securely encrypted and signed, verified by a secure boot certificate signature database, and loaded into a buffer memory for execution, ensuring the security of both the main application and non-application files.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If secure boot certificate verification is enforced for all firmware applications, then system security is improved, but firmware applications with powerful functions (e.g., code interpreters) cannot be executed

Engineering Contradiction:

Improvesystem securityVSAvoidfirmware application execution capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The verification process is segmented into two distinct paths: traditional secure boot certificate verification for standard firmware, and alternative secure encryption signature verification for firmware applications requiring powerful functions. This segmentation allows each type of firmware to undergo appropriate verification without blocking execution of legitimate applications.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A boot manager is introduced as an intermediary component that coordinates between the secure boot certificate verification mechanism and the secure encryption signature verification mechanism. The boot manager determines which verification path to use based on the firmware type, enabling both security mechanisms to coexist and function properly.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If firmware applications are required to obtain valid digital signatures from OEM, then security is improved, but firmware applications cannot be updated or modified after initial authorization

Engineering Contradiction:

Improvefirmware securityVSAvoidfirmware update capability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The secure encryption signature is applied to the firmware application module before it is loaded into the computer apparatus. This preliminary signing action enables the firmware to be verified and executed without requiring real-time OEM authorization, facilitating updates and modifications while maintaining security through pre-established cryptographic verification.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If code interpreters are allowed to execute in secure boot mode, then functionality is improved, but security risks increase due to potential malicious code execution

Engineering Contradiction:

Improvecode execution capabilityVSAvoidsecurity risk from malicious code

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The verification mechanism is made dynamic by allowing different verification approaches based on the firmware type. For code interpreters and firmware requiring powerful functions, the system dynamically switches to alternative secure encryption signature verification instead of strict secure boot certificate verification, enabling functionality while maintaining security through cryptographic validation.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11423149B2Method and computer apparatus securely executing extensible firmware application

Publication Date: 2022.08.23 INSYDE SOFTWARE CORP

AI summary

A method securely executing an extensible firmware application is performed by a computer apparatus. The computer apparatus includes a firmware volume and a boot loader. The firmware volume includes a firmware application module to be executed, has passed a security check, and is attached with a secure encryption signature. The boot loader is attached with a first valid digital signature, and is verifiable by a secure boot certificate signature database of the computer apparatus. When the firmware application module is executed, the boot loader or the secure boot certificate signature database of the computer apparatus first verifies a secure encryption signature of the firmware volume, and the boot loader then loads the firmware application module to a buffer memory for further reading and execution, such that execution of the firmware application module is allowed and is executed securely in a secure boot mode under supervision of the boot loader.