Physical-Layer Waveform Monitoring for Wired Network Tampering

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Solution Overview

Problem

Current wired network monitoring and security methods fail to effectively detect unauthorized device connections or substitutions by analyzing physical layer signal waveforms, leading to potential security breaches.

Innovation Solution

A method and apparatus that utilize physical layer analysis to monitor and secure wired networks by detecting changes in signal waveforms, enabling the identification of authorized device connections and preventing unauthorized substitutions through waveform analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If physical layer signal waveform analysis is implemented for network monitoring, then network security detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvenetwork security detection capabilityVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A TAP (Test Access Point) device is introduced as an intermediary component that interfaces between the wired network and the monitoring system. The TAP captures signal waveforms from the network medium and presents them to the monitoring system for analysis, thereby enabling security monitoring without directly complicating the existing network infrastructure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional network monitoring methods that rely on higher-layer protocol analysis with physical layer waveform analysis. By substituting mechanical/electronic signal capture and digital waveform processing approaches, the system achieves more fundamental security detection at the physical layer without requiring complex protocol interpretation.

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

2Measurement precision

If waveform analysis is used to detect unauthorized device connections, then measurement precision of network changes is improved, but difficulty of detecting and measuring increases

Engineering Contradiction:
Improvedetection accuracy of device connectionsVSAvoidcomplexity of waveform analysis
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The monitoring system performs preliminary actions by continuously capturing and storing signal waveforms from the network medium before actual security events occur. This creates a baseline of normal network traffic patterns, enabling comparison and detection of unauthorized connections or device substitutions when deviations are detected.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system detects security events by monitoring changes in waveform parameters such as signal amplitude, frequency, rise time, and fall time. When an unauthorized device is connected or substituted, these physical layer parameters change in characteristic ways that the system can identify through comparison with stored baseline waveforms.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3535625B1System and method for using signal waveform analysis for detecting a change in a wired network
Publication Date: 2021.02.24 ARILOU INFORMATION SECURITY TECH LTD
  • EP3535625B1 patent drawingFigure 1
  • EP3535625B1 patent drawingFigure 2
  • EP3535625B1 patent drawingFigure 3

AI summary

An analyzer for monitoring a configuration of a wired network medium that is used for communication between multiple devices. The configuration change includes an additional device tapping to the medium for eavesdropping, or the substituting one of the devices. The analyzer is connected to the medium for receiving, storing, and analyzing waveforms of the physical-layer signals propagated over the medium. The analysis includes comparing the received signals to reference signals, and notifying upon detecting a difference according to pre-set criteria. The analysis may be time or frequency-domain based, and may use a feed-forward Artificial Neural Network (ANN). The wired network may be an automotive or in-vehicle network, PAN, LAN, MAN, or WAN, may use balanced or unbalanced signaling, and may be configured as point-to- point or multi-point topology. The analyzer may be connected at an end of the medium, and may be integrated with one of the devices.