Vehicular Digital Key Authentication With Disposable Access Keys

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Solution Overview

Problem

Existing vehicular digital key systems face challenges in balancing security and user convenience, particularly when mobile terminals with varying processing capacities and communication availability are used, leading to increased processing loads and potential access limitations.

Innovation Solution

A vehicular digital key system where a server generates unique service keys for mobile terminals, distributing disposable one-time authentication keys with expiration dates, which are managed and replaced by the mobile terminal, ensuring security and convenience by allowing multiple keys and continuous access even in communication-limited environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the mobile terminal generates and manages authentication keys locally, then user convenience is improved, but the processing load on the mobile terminal increases

Engineering Contradiction:

Improveuser convenienceVSAvoidprocessing load

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The authentication key management function is segmented into two parts: the server generates and distributes one-time authentication keys, while the mobile terminal only stores and transmits these keys. This segmentation reduces the processing load on the mobile terminal while maintaining user convenience.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The server acts as an intermediary that handles the complex key generation and management tasks. Instead of the mobile terminal generating keys locally, the server generates one-time authentication keys and distributes them to the terminal, reducing the terminal's processing burden.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If traditional authentication methods are used, then system simplicity is maintained, but security against replay attacks deteriorates

Engineering Contradiction:

Improvesystem simplicityVSAvoidsecurity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The authentication system transitions from static authentication keys to dynamic one-time authentication keys that are valid only for a single use and have expiration dates. This dynamic approach enhances security against replay attacks while maintaining relative system simplicity through automated key management.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses disposable one-time authentication keys that are discarded after a single use or when they expire. This approach provides strong security against replay attacks while keeping the system simple, as the keys are automatically generated and managed by the server without requiring complex client-side security mechanisms.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS12479400B2Vehicular digital key system, vehicular digital key management method, vehicular device, and mobile terminal

Publication Date: 2025.11.25 DENSO CORP

AI summary

A server issues a service key for using a designated vehicle and a plurality of one-time authentication keys based on a request from the mobile terminal, and distributes the one-time authentication key to the mobile terminal. The one-time authentication key is a disposable authentication key generated based on the service key, and has an expiration date. The one-time authentication key is consumed when the vehicular device authenticates the mobile terminal as a communication partner. The mobile terminal replaces the one-time authentication key stored in the mobile terminal at any time.