Passive Access Control Using Electronic Distance Measurement
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Solution Overview
Problem
Current passive access systems using mobile devices as vehicle keys face challenges in convenience and security, particularly in defending against relay attacks, as they require specific operator actions and lack complete protection against extended radio communication links.
Innovation Solution
Implementing an electronic distance measurement method between the mobile device and an interaction unit, where access is allowed only if the distance is within a permitted range, using signal propagation time measurement to prevent manipulation and ensure the mobile device is in close proximity to the interaction unit, thereby preventing relay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If passive access control using mobile devices is implemented, then convenience is improved, but security against relay attacks deteriorates
Solution Approach 1:
The patent introduces an intermediary distance measurement mechanism that acts as a mediator between the mobile device and the access control system. This intermediary verification layer prevents direct relay attacks by confirming the actual physical distance, thus maintaining convenience while enhancing security.
Solution Approach 2:
The patent changes the verification parameter from simple presence detection to precise distance measurement. By measuring and verifying the distance parameter between the mobile device and the interaction unit, the system maintains passive convenience while adding a security layer that prevents relay attacks.
2Reliability
If distance measurement verification is implemented, then security against relay attacks is improved, but device complexity increases
Solution Approach 1:
The patent makes both the mobile device and the interaction unit capable of performing distance measurement functions. This multi-functionality allows the system to use existing bidirectional communication capabilities for both authorization exchange and distance verification, reducing the need for separate dedicated hardware and thus limiting complexity increase.
3Measurement precision
If bidirectional distance measurement is performed, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The patent performs distance measurement as part of the normal access control protocol initiation. By combining distance verification with the existing authorization exchange sequence, the system achieves precise bidirectional measurement without requiring separate dedicated measurement phases, thus limiting additional energy consumption.
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
This approach enhances both convenience and security by ensuring the mobile device is accurately within the permitted distance for access, effectively detecting and preventing relay attacks while allowing secure and convenient access.
Implementation Method 1
The electronic distance measuring device is designed in such a way that manipulation of the distance measurement is impossible. This is ensured by, firstly, that the distance measurement is based on a signal time-of-flight measurement
Data Source
Figure 1
AI summary
The invention relates to a method for passive access control using a mobile device (14) serving as a key and an interaction unit, wherein the mobile device (14) and the interaction unit (12) each have at least one data communication device (20) for exchanging authorization information. The method includes steps of performing an electronic distance measurement (18) between the mobile device (14) and the interaction unit (12); and allowing access and/or interaction only if the distance (30) between the mobile device (14) and the interaction unit (12) is within a permissible distance (28). The invention aims to increase both the convenience and the security of passive access control using a mobile device serving as a key.