USB Input Device Firmware Lock State Mechanism

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Solution Overview

Problem

USB input devices, such as cameras and microphones, are vulnerable to malicious firmware updates due to the lack of secure firmware installation and update processes, which can compromise biometric data security.

Innovation Solution

Implementing a firmware lock/unlock state mechanism on the USB input device controller, where the controller receives unlock requests from a host, determines their validity, and updates its firmware lock state accordingly, ensuring that only authenticated firmware updates are installed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If firmware update functionality is enabled on USB input devices, then device adaptability and maintenance capability are improved, but security vulnerability to malicious firmware increases

Engineering Contradiction:
Improvefirmware update capabilityVSAvoidsecurity vulnerability
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a lock state mechanism that is set before firmware update operations. The controller is placed in a locked state by default, preventing unauthorized firmware updates. This preliminary security measure ensures that even though firmware update capability exists, it cannot be exercised without proper authorization, thus resolving the contradiction between adaptability and security vulnerability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary authentication mechanism between the firmware update request and the actual update execution. The host computing system must provide valid authentication credentials, and the controller verifies these credentials before allowing the firmware update. This intermediary layer acts as a mediator that enables legitimate updates while blocking malicious ones, thus maintaining both adaptability and security

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If firmware lock state mechanism is implemented, then security against malicious firmware is improved, but device complexity increases

Engineering Contradiction:
Improvemalicious firmware protectionVSAvoidcontroller complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the firmware update process into distinct states (locked and unlocked) and separate authentication verification from the actual update execution. The lock state mechanism is implemented as a separate control layer that manages access to the firmware update functionality. This segmentation allows the security mechanism to be added without significantly complicating the core firmware update logic, as the security layer operates independently

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the state parameter of the controller between locked and unlocked states to control firmware update accessibility. This parameter-based approach allows the same hardware and basic software architecture to support both secure and update modes without requiring additional complex components. The lock state acts as a simple binary parameter that gates access to firmware update functionality, minimizing the increase in device complexity

Inventive Principle:
Principle #35Parameter changes

3Reliability

If authentication verification is performed before firmware installation, then firmware integrity is improved, but update process time increases

Engineering Contradiction:
Improvefirmware integrityVSAvoidupdate process time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs authentication verification as a preliminary action before the actual firmware installation process. The host computing system prepares authentication credentials in advance, and the controller verifies these credentials before accepting the firmware payload. This preliminary authentication ensures firmware integrity is verified before any installation time is consumed, thus maintaining high reliability while minimizing the impact on overall update process time

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3966713B1Securing firmware installation on USB input device
Publication Date: 2025.02.19 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3966713B1 patent drawingFigure 1
  • EP3966713B1 patent drawingFigure 2
  • EP3966713B1 patent drawingFigure 3

AI summary

One example provides, on a USB input device, a method comprising receiving an unlock request to change a firmware lock state of a controller of the USB input device from a locked state to an unlocked state, determining whether the unlock request is valid or invalid, when the unlock request is valid, updating the firmware lock state from the locked state to the unlocked state and sending a process completion message, when the unlock request is invalid, sending the process completion message without updating the firmware lock state, receiving a firmware update request, determining whether the firmware lock state is in the locked state or the unlocked state, receiving a firmware payload, authenticating data of the firmware payload, and when the firmware lock state is determined to be in the unlocked state and when the data of the firmware payload is authenticated, then installing the firmware payload.