Vehicle Key Chip Control for Secure Smartphone Access

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing vehicles, especially those not designed for car-sharing or car-on-demand scenarios, lack secure mechanisms to prevent unauthorized access and use, as they often rely on a vehicle key that can be stolen during a break-in.

Innovation Solution

A device, referred to as a CDIS box, integrates a key chip with non-manipulable firmware that transmits key or immobilizer signals only after authorization by a central computer via wireless communication, using a mobile device for authentication and cryptographic security to prevent misuse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a vehicle key is stored in the car itself for easy access, then ease of operation is improved, but security against theft is worsened as the key can fall into thieves' hands during break-in

Engineering Contradiction:
Improvevehicle access convenienceVSAvoidsecurity against unauthorized access
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system segments the key functionality into two parts: a key chip stored in the vehicle and a control module that communicates with a mobile device. The key chip contains the cryptographic credentials while the control module manages communication and authorization, separating security-critical functions from user interface functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control module acts as an intermediary between the mobile device and the key chip. It receives authentication data from the mobile device, verifies it against the key chip, and only then activates the key signal transmission, providing an additional security layer that prevents direct access to the key chip.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If key signals are transmitted via wireless communication for contactless access, then ease of operation is improved, but vulnerability to unauthorized interception is worsened

Engineering Contradiction:
Improvecontactless vehicle accessVSAvoidrisk of signal interception
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system changes the parameters of wireless communication by using encrypted data transmission between the mobile device and control module, and authenticated signal transmission between the control module and key chip. This transforms the communication from plain text to cryptographically secured exchanges.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical key systems with an electronic/cryptographic system. Instead of physical key insertion, the system uses wireless authenticated communication with cryptographic verification, substituting mechanical security with digital security mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a central computer authorization system is implemented for security, then reliability is improved, but device complexity is worsened due to additional components

Engineering Contradiction:
Improveauthorization securityVSAvoidnumber of system components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control module serves multiple functions: it communicates with the mobile device, verifies authentication data, manages the key chip, and transmits authorized signals to the vehicle's immobilizer and locking systems. This multi-functionality reduces the need for separate dedicated components for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system merges the authorization logic and key management functions into a single control module that integrates communication with the mobile device and control of the key chip. This consolidation reduces system complexity compared to having separate authorization server, key manager, and signal transmitter components.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3902707B1Concept for provision of a key signal or an immobiliser signal for a vehicle
Publication Date: 2025.08.27 VOLKSWAGEN AG
  • EP3902707B1 patent drawingFigure 1a~1b
  • EP3902707B1 patent drawingFigure 1c
  • EP3902707B1 patent drawingFigure 2a~2b

AI summary

The invention relates to a method for a device for a vehicle, to the device for the vehicle, to a method and a device for a central computer, to a method and a device for a mobile device, and to corresponding computer programs. The device for a the vehicle comprises a key chip. The method for the device for the vehicle comprises obtaining information relating to a release of a key signal or an immobiliser signal by a central computer via a wireless mobile communication system. The release of the key signal communicates a release of an unlocking or locking function of a central locking system of the vehicle by the central computer. The release of the immobiliser signal communicates a release of a deactivating or activating function of an immobiliser by the central computer. The method comprises the provision of a control signal for the key chip based on the information relating to the release of the key signal or the immobiliser signal. The control signal is designed to allow the key chip to provide the key signal or the immobiliser signal. The method comprises the provision of the key signal or the immobiliser signal, by the key chip, via a wireless communication link for a central locking system or an immobiliser system of the vehicle, after obtaining the control signal.