Smartphone Digital Key Preventing Relay Attacks via Movement Authentication

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Solution Overview

Problem

Keyless entry systems in vehicles are vulnerable to relay attacks, where a signal repeater bypasses encryption and security protocols, allowing unauthorized access by mimicking the electronic key's location, and existing solutions like placing keys in Faraday cages are not satisfactory.

Innovation Solution

A computer system and portable electronic device combination that uses machine learning to train a model on user movement signals, generating direction vectors and characteristic vectors to authenticate access to vehicles, incorporating sensors like accelerometers and gyroscopes, and applying supervised classification algorithms to prevent relay attacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If keyless entry systems are implemented, then ease of operation is improved, but security against relay attacks deteriorates

Engineering Contradiction:
Improvecontactless accessVSAvoidsecurity against relay attacks
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary actions by training a machine learning model in advance with movement data collected during acquisition sessions. The model learns to recognize legitimate user movement patterns before actual authentication occurs, enabling it to detect and prevent relay attacks in real-time without compromising the convenience of contactless access

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary machine learning model that acts as a mediator between the physical key and the vehicle's authentication system. This model analyzes movement signals and determines whether the key's movement is legitimate or part of a relay attack, thereby enhancing security while maintaining the ease of contactless operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If Faraday cages are used to prevent relay attacks, then security is improved, but device complexity and ease of operation worsen

Engineering Contradiction:
Improvesecurity against relay attacksVSAvoidFaraday cage requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/physical Faraday cage solution with a computational approach using machine learning. Instead of using electromagnetic shielding to block signals, the system uses an ML model to analyze movement patterns and detect relay attacks, thereby maintaining security without adding physical complexity or restricting user operations

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

3Measurement precision

If movement signals are collected and analyzed, then security precision is improved, but loss of time increases

Engineering Contradiction:
Improvemovement authenticationVSAvoidtraining and processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs the time-consuming training process in advance during acquisition sessions, so that when actual authentication is needed, the pre-trained model can quickly and accurately analyze movement signals without causing noticeable delays to the user. This preliminary preparation resolves the contradiction between achieving high measurement precision and minimizing time loss

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11338772B2Digital keys and systems for preventing relay attacks
Publication Date: 2022.05.24 CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH
  • US11338772B2 patent drawing
  • US11338772B2 patent drawing

AI summary

Computer systems for training a machine learning model for preventing relay attacks. Including portable electronic devices capable of controlling the opening or closing, contactlessly, of an access to a road vehicle on the basis of a pretrained machine learning model. The general principle is based on the use of smartphones as a digital key for accessing a road vehicle. Machine learning is used to train a learning model capable of predicting the movement of a smartphone of this type as it approaches or moves away from the road vehicle. Subsequently, access to the road vehicle is authorized only when same receives the information on the movement of the smartphone.