Vehicle Digital Key Communication Through Backend Mediation

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Solution Overview

Problem

Existing digital vehicle key systems lack the capability for secure communication between a terminal and a vehicle over long distances, limiting the sharing and management of digital keys to immediate vicinity.

Innovation Solution

Implementing encryption key pairs on both the terminal and vehicle, combined with a third-party attestation process, enables secure and indirect communication via a backend server, allowing key sharing and data exchange over extended distances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If direct contact between terminal and vehicle is used for secure communication, then secure data exchange is enabled, but communication is limited to immediate vicinity only

Engineering Contradiction:

Improvesecure data exchangeVSAvoidcommunication distance

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a backend server as an intermediary component that enables indirect communication between the terminal and vehicle. The backend server receives encrypted data from the terminal and forwards it to the vehicle, or receives data from the vehicle and sends it to the terminal, all while maintaining security through encryption keys. This intermediary approach allows secure communication without requiring direct physical contact between the terminal and vehicle, thus extending communication range while preserving security.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If encryption key pairs are exchanged between terminal and vehicle, then secure communication over long distances is enabled, but system complexity increases

Engineering Contradiction:

Improvecommunication distanceVSAvoidkey exchange mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The backend server acts as a mediator that simplifies the key exchange process. Instead of the terminal and vehicle directly managing complex key exchange protocols, the backend server handles the encryption key distribution. The terminal provides its public key to the backend, which then securely transmits it to the vehicle. This intermediary approach reduces the complexity of direct peer-to-peer key management while enabling long-distance secure communication.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary key setup actions during the pairing process. The terminal and vehicle exchange public keys and establish encryption key pairs in advance before actual data transmission occurs. This preliminary configuration allows subsequent communication to proceed securely without repeatedly managing complex key exchange protocols, thus reducing operational complexity while maintaining long-distance capability.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If public keys are transmitted from vehicle to terminal, then key sharing capability is improved, but security risks increase if private keys are exposed

Engineering Contradiction:

Improvekey sharing capabilityVSAvoidprivate key exposure risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The backend server serves as a secure intermediary that handles public key transmissions. When the vehicle needs to share its public key with the terminal, or when the terminal needs to verify the vehicle's public key, the backend server facilitates this exchange through secure channels. This intermediary approach ensures that only the necessary public key information is transmitted, while private keys remain protected and never exposed during the communication process, thus enabling key sharing without compromising security.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses public key copies for communication while preserving the original private keys. The terminal and vehicle exchange public key copies rather than sensitive private key material. The backend server manages these public key copies, allowing verification and sharing operations to proceed without exposing the underlying private keys. This copying approach enables key sharing capability while maintaining security by ensuring that only non-sensitive public information is transmitted.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS20250279890A1Improved Communication Between a Digital Key Device and a Vehicle

Publication Date: 2025.09.04 BAYERISCHE MOTOREN WERKE AG

AI summary

A method for communicating data between a terminal, which has a signature key pair for a vehicle, and the vehicle, is provided. A public vehicle encryption key is transmitted from the vehicle to the terminal. A public terminal encryption key is combined with an identification feature of the terminal or a third party, the combined public terminal encryption key is transmitted from the terminal to the vehicle, and the identification feature of the combined public terminal encryption key is verified by the vehicle. This enables confidential indirect communication between the vehicle and the terminal via the third party based on the vehicle encryption key and the terminal encryption key.