Vehicle Access Radio Link Security Against Relay Attacks

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Solution Overview

Problem

Existing radio-based access systems for vehicles are vulnerable to relay station attacks, where an attacker can intercept and extend the radio link between the vehicle and an ID transmitter, allowing unauthorized access even when the transmitter is outside the vehicle's range, due to the susceptibility of standardized communication protocols like Bluetooth to frequency changes and interference.

Innovation Solution

Establishing a secure and encrypted data connection between the ID transmitter and the vehicle's control device using proprietary connection parameters for frequency spread methods, which are changed after initial encryption, preventing attackers from tracking or manipulating the communication link by dynamically altering the frequency hopping sequence and dwell times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standardized communication protocols like Bluetooth with frequency hopping are used, then interference resistance and basic security are improved, but vulnerability to relay station attacks increases due to trackable frequency patterns

Engineering Contradiction:
Improveinterference resistanceVSAvoidrelay station attack vulnerability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the frequency hopping pattern changeable during communication. The control unit and ID transmitter dynamically alter the frequency hopping sequence based on randomly generated numbers exchanged during the communication process, making the pattern unpredictable and preventing relay station attacks while maintaining interference resistance

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the frequency hopping parameters (carrier frequencies and dwell times) during the communication process. By exchanging randomly generated numbers and using these to modify the frequency pattern, the system transforms static connection parameters into dynamic ones, preventing attackers from tracking the communication link

Inventive Principle:
Principle #35Parameter changes

2Reliability

If encrypted data connection is continuously active, then security against eavesdropping is improved, but energy consumption increases

Engineering Contradiction:
Improvesecurity against eavesdroppingVSAvoidenergy consumption of ID transmitter
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by activating the encrypted data connection and frequency pattern changes only when vehicle access functions are actually requested. The system switches between a low-power state and an encrypted communication state based on trigger events, reducing energy consumption while maintaining security when needed

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses event-driven activation where the ID transmitter and control unit automatically establish encrypted connections in response to specific access requests. This self-service mechanism ensures security is maintained through encryption only when necessary, avoiding continuous energy consumption

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3444150B1Securing a radio communication for vehicle access systems
Publication Date: 2020.11.04 HUF HÜLSBECK & FÜRST GMBH & CO KG
  • EP3444150B1 patent drawingFigure 1
  • EP3444150B1 patent drawingFigure 2

AI summary

A method for the secure transmission of data between a mobile ID transmitter and a motor vehicle control unit (99). First, a wireless communication link is established between the ID transmitter and the control unit (30), whereby a connection is established using a spread-frequency method with first connection parameters (30). Encrypted data communication (40) is established on this communication link. Second connection parameters are generated in the mobile ID transmitter or the control unit and the second connection parameters are transmitted via the encrypted data communication of the wireless communication link (50).Subsequently, the communication link is switched to use the second connection parameters of the spread spectrum method in the ID transmitter and the control unit (60) and data communication is continued via the switched communication link (70).