Keyless Entry Authentication Using Signal Delay Against Relay Attacks
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Solution Overview
Problem
Keyless entry systems are vulnerable to relay attacks, where the legitimate signal is intercepted and copied, allowing unauthorized access.
Innovation Solution
A device with a processing system and memory that selects a circuit from a key, wirelessly transmits a challenge signal, and analyzes the response signal's power level and delay to authenticate the key and enable the entry system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If keyless entry systems use wireless signal transmission for convenient access, then ease of operation is improved, but vulnerability to relay attacks increases
Solution Approach 1:
The system performs preliminary authentication by analyzing response signal characteristics (power level, delay, circuit selection) before granting entry. This advance verification prevents relay attacks by ensuring the responding key is physically present and authentic, not merely a copied signal.
Solution Approach 2:
The system implements feedback mechanisms by transmitting challenge signals and analyzing the key's response signals. The vehicle processor evaluates multiple parameters (power level, delay, circuit identification) of the response to authenticate the key, creating a closed-loop verification system that prevents unauthorized access.
2Reliability
If the system transmits challenge signals and analyzes multiple response parameters for security, then reliability is improved, but device complexity increases
Solution Approach 1:
The authentication process is segmented into distinct analysis components: power level detection, delay measurement, and circuit identification. Each parameter is analyzed separately by dedicated processing functions, making the complex authentication process manageable and implementable through modular system design.
Solution Approach 2:
The system uses parameter changes in the response signal (power level variations, delay differences, circuit response characteristics) as authentication criteria. By monitoring these natural parameter variations that occur based on physical key proximity and circuit behavior, the system achieves reliable authentication without requiring overly complex analysis mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively protects keyless entry systems from relay attacks by ensuring that only authorized keys can enable the entry system, based on precise analysis of response signals.
Implementation Method 1
a vehicle processor of the entry system selects a circuit from a plurality of circuits of a key remote from the vehicle and wirelessly transmits a challenge signal to the key, the challenge signal specifying the selected circuit
Implementation Method 2
The key is directed to provide a response signal having a delay associated with the selected circuit and a power associated with the selected circuit
Data Source
AI summary
Aspects of the subject disclosure may include, for example, a device in which a processing system of a remote entry system selects a first circuit from a plurality of circuits of a key remote from the device; wirelessly transmits a first challenge signal to the key, the first challenge signal specifying the first circuit; and wirelessly receives a first response signal from the key, the first response signal having a first response signal power level and a first response signal delay with respect to the first challenge signal. The processing system analyzes the first response signal by comparing the first response signal power level and the first response signal delay respectively with a predetermined first signal power and predetermined first time delay associated with the first circuit; and, in accordance with the comparing, determines whether to enable the entry system. Other embodiments are disclosed.