Vehicle Electronic Key System Relay Attack Prevention

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Solution Overview

Problem

Existing vehicle electronic key systems are vulnerable to relay attacks where unauthorized users can bypass authentication by using a relay device to simulate the proximity of a portable device, leading to unauthorized vehicle control.

Innovation Solution

The system employs multiple in-vehicle communication devices that communicate with each other to generate distance-related information, and an authentication device that only allows vehicle control if all inter-device distances are within predetermined normal ranges, preventing unauthorized access by detecting deviations in these distances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wireless communication authentication is used for vehicle control, then ease of operation is improved, but reliability deteriorates due to vulnerability to relay attacks

Engineering Contradiction:

Improvewireless authenticationVSAvoidsecurity against relay attacks

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces the traditional single-point wireless authentication mechanism with a multi-point geometric verification system. Instead of relying solely on signal presence detection, the system uses multiple in-vehicle communication devices to establish triangular geometric relationships with the portable device, substituting cryptographic relay attack resistance with geometric spatial verification.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent adds a spatial geometric dimension to the authentication process. By introducing distance-related information and inter-device distance measurements, the system transforms a one-dimensional signal detection problem into a multi-dimensional geometric verification problem, enabling detection of relay attacks through spatial relationship validation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If multiple in-vehicle communication devices are used for distance verification, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improverelay attack detectionVSAvoidnumber of communication devices

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes each in-vehicle communication device multi-functional by enabling them to perform both external wireless authentication with portable devices and internal mutual authentication with each other. This universal functionality allows the same hardware components to serve dual purposes, reducing the need for separate dedicated devices for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the authentication function and distance verification function into a unified system where multiple communication devices work together. By combining these functions and using the communication devices for both external and internal verification, the system achieves enhanced security without proportionally increasing device count.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If inter-device distance verification is implemented, then security against relay attacks is improved, but measurement precision requirements increase

Engineering Contradiction:

Improverelay attack preventionVSAvoiddistance measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where distance-related information from multiple communication devices is continuously monitored and used to adjust authentication decisions. The system uses the inter-device distance measurements as feedback to verify geometric relationships, allowing for dynamic validation rather than static threshold checking.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the authentication parameter from simple signal presence to composite geometric parameters including distance-related information and inter-device distances. By transforming the verification criterion into a multi-parameter geometric validation system, the patent reduces dependence on single-point precision while maintaining overall security.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11208074B2Vehicle electronic key system

Publication Date: 2021.12.28 DENSO CORP

AI summary

A vehicle electronic key system includes a plurality of in-vehicle communication devices and an authentication device. Each of the plurality of in-vehicle communication devices communicates wirelessly with another in-vehicle communication device, and based on a signal transmitted from the another in-vehicle communication device, generate distance-related information that directly or indirectly indicates a distance to the another in-vehicle communication device. The authentication device specify a plurality of inter-communication device distances based on the distance-related information generated by the plurality of in-vehicle communication devices, and does not execute a vehicle control when at least one of the plurality of inter-communication device distances deviates from a predetermined normal range.