Digital Key Sharing Between User and Third-Party Terminals

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Solution Overview

Problem

Existing key information sharing systems face challenges in ensuring security and convenience when sharing or lending a control device, such as a vehicle, between a user terminal and a third-party terminal, often requiring the user to lend their terminal directly to the third party.

Innovation Solution

A key information sharing system that includes a delivery device and a user terminal capable of adding additional information to the key information, allowing secure transfer between the user and third-party terminals without direct intervention from the delivery device, while also enabling restrictions and management of the control operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If key information is generated in the user terminal and transferred to the third-party terminal, then sharing convenience is improved, but security of the object decreases

Engineering Contradiction:
Improvesharing convenienceVSAvoidsecurity of the object
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The delivery device serves as an intermediary between the user terminal and third-party terminal. It generates the key information and adds transfer permission information, then delivers it to the user terminal. This mediator approach allows secure key distribution without requiring the user terminal to generate and directly transfer sensitive key information, thus maintaining security while enabling convenient sharing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The key information is segmented into two parts: the key information itself and the transfer permission information. The transfer permission information acts as a separate control mechanism that enables or disables sharing without exposing the core key information. This segmentation allows the system to grant sharing rights securely by controlling the permission flag rather than the key material itself.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the user lends the user terminal itself to the third party for object utilization, then security is maintained, but convenience significantly decreases

Engineering Contradiction:
ImprovesecurityVSAvoidconvenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Instead of requiring the user to physically lend their terminal, the system creates a functional copy of the key information and delivers it to the third-party terminal through the delivery device. The third party receives a copied version of the necessary authentication data, enabling them to use the object independently without needing access to the user's actual terminal device.

Inventive Principle:
Principle #26Copying

3Speed

If key information is transferred from user terminal to third-party terminal without delivery device intervention, then sharing speed is improved, but security control capability decreases

Engineering Contradiction:
Improvesharing speedVSAvoidsecurity control capability
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The delivery device performs preliminary actions by pre-generating the key information and embedding transfer permission information before delivery to the user terminal. This advance preparation enables rapid transfer to the third party without requiring real-time security verification, as the permission framework is already established. The security control is implemented in advance rather than during the transfer process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3483844B1Key information sharing system, delivery device and user terminal
Publication Date: 2025.09.17 TOYOTA JIDOSHA KK
  • EP3483844B1 patent drawingFigure 1
  • EP3483844B1 patent drawingFigure 2
  • EP3483844B1 patent drawingFigure 3

AI summary

A key information sharing system includes a delivery device (400) that delivers key information as first information (I1) for a control device (11) equipped in an object (10) and a user terminal (200a) that receives the first information (II) delivered from the delivery device (400). The delivery device (400) adds second information (12) that allows the first information (II) to be transferred between the user terminal (200a) and a third-party terminal (200b) without the delivery device (400), to the first information (11) to be delivered to the user terminal (200a). The user terminal (200a) transmits the first information (I1) to the third-party terminal (200b) in response to an input operation by a user, when the user terminal (200a) receives the first information (II) to which the second information (I2) has been added.