Digital Key Sharing Roles for Secure Multi-Level Access

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Solution Overview

Problem

Existing digital key systems allow only single-level sharing from an owner device to a friend device, limiting the ability of friend devices to share keys with other devices, which affects user experience in scenarios like vehicle wash, repair, or hotel scenarios.

Innovation Solution

Introduce additional device roles and a method for multi-level digital key sharing by allowing a second device to share keys with a third device, using immobilizer tokens of different levels and setting permission configurations to manage sharing permissions and security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If friend device cannot share digital key with other devices, then security is maintained, but user experience deteriorates in scenarios like vehicle wash or repair

Engineering Contradiction:
Improveuser experienceVSAvoidkey sharing capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent segments the digital key sharing capability by introducing different types of digital keys (owner device digital key and friend device digital key) with different sharing permissions. The owner device digital key can be shared with friend devices, and friend device digital keys can be shared with other friend devices, creating a hierarchical segmentation that enables multi-level sharing while maintaining security control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a new dimension to the key sharing system by introducing a second-level sharing capability. Instead of allowing only direct sharing from owner to friend, the system now enables friend devices to share with other friend devices, creating a multi-dimensional sharing structure that expands versatility without compromising the original security model.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If digital key is left at vehicle location for service, then service can be performed, but convenience deteriorates as key cannot be carried around

Engineering Contradiction:
ImproveconvenienceVSAvoidkey portability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent implements a digital copying mechanism where the friend device digital key is created as a copy of the owner device digital key with appropriate permissions. This digital copy can be transferred to multiple devices (second friend device, third friend device, etc.), eliminating the need to physically leave the original key at the service location while maintaining secure access control.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If multi-level sharing is enabled, then versatility improves, but system complexity increases

Engineering Contradiction:
Improvesharing flexibilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by assigning different properties to different types of digital keys. Owner device digital keys have full sharing capabilities, while friend device digital keys have restricted sharing capabilities (can only share with other friend devices). This localized differentiation of key properties enables versatile multi-level sharing while keeping the system manageable through clear, role-based permission structures.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4700725A1Digital key sharing method, system, and terminal
Publication Date: 2026.02.25 BOE TECHNOLOGY GROUP CO LTD
  • EP4700725A1 patent drawingFigure 1
  • EP4700725A1 patent drawingFigure 2
  • EP4700725A1 patent drawingFigure 3

AI summary

The present disclosure provides a digital key sharing method, a system, and a terminal, for use in solving the problem of single sharing objects in key sharing scenes by addition of device roles in addition to friend devices and settings based on digital key standards. The method comprises: a second device sends to a third device a key creation request, used for instructing the third device to generate information to be authenticated, wherein the second device has a digital key, and the digital key of the second device is obtained by performing digital key sharing by a first device; the second device receives a key signing request sent by the third device, authenticates the information to be authenticated in the key signing request, and generates key authentication information; the second device sends to the third device a key import request, used for instructing the third device to save the key authentication information in the key import request, wherein the key authentication information is used for determining a digital key of the third device.