Hardware Trojan Detection Using Clock-Harmonic Backscatter

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Solution Overview

Problem

Existing methods for detecting hardware Trojans in integrated circuits (ICs) are ineffective in identifying stealthy, inactive Trojans due to their reliance on functional testing and traditional side channels that are susceptible to noise and interference, and require destructive or expensive analysis.

Innovation Solution

A non-destructive, off-chip backscattering side channel technique that measures impedance-based modulations in ICs using a carrier wave to detect harmonics of the clock frequency, allowing for accurate identification of inactive Trojans by analyzing amplitude ratios of backscattered signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional functional testing and side channel methods are used to detect hardware Trojans, then detection can be performed, but detection accuracy is low for inactive Trojans and false positives occur due to noise and interference

Engineering Contradiction:
Improvedetection accuracyVSAvoidnoise and interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary measurement approach by using backscattered signal measurements at different frequencies as a mediator to indirectly detect the presence of hardware Trojans. Instead of directly observing circuit behavior, the method measures the backscattered signals and uses frequency-dependent amplitude ratios as an intermediary indicator that reveals Trojan presence without being affected by operational noise and interference

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the measurement parameter from time-domain side channel signals to frequency-domain backscattered signal amplitudes. By measuring amplitude ratios at different frequencies and comparing them to reference values, the method transforms the detection problem into a frequency-based parameter comparison that is inherently more resistant to noise and interference

Inventive Principle:
Principle #35Parameter changes

2Reliability

If destructive or expensive analysis methods are used to detect hardware Trojans, then detection thoroughness improves, but manufacturing cost and time increase

Engineering Contradiction:
Improvedetection thoroughnessVSAvoidmanufacturing cost and time
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent enables the integrated circuit to self-reveal its security status through passive backscattered signal measurements. The method uses the circuit's own operational signals to detect Trojans without requiring external destructive analysis or expensive specialized equipment, making the detection process as easy and inexpensive as regular manufacturing testing

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical/destructive physical analysis methods with electromagnetic field-based backscattering measurements. Instead of physically dissecting or destroying the circuit for analysis, the method uses non-contact RF signal measurements to detect Trojans, eliminating the need for destructive procedures while maintaining detection effectiveness

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

3Ease of operation

If conventional side channel methods are used, then detection can be performed, but the methods are susceptible to noise and require complex signal processing

Engineering Contradiction:
Improvesignal processing complexityVSAvoidnoise susceptibility
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary action by establishing reference amplitude ratio values from known good circuits before actual detection. These pre-established references are stored and used to simplify subsequent detection operations, allowing direct comparison without complex real-time signal processing or noise filtering algorithms

Inventive Principle:
Principle #10Preliminary action

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

The backscattering side channel technique provides high detection accuracy for inactive Trojans, is resilient to manufacturing variations, and can differentiate between genuine and counterfeit ICs, reducing false positives and operational interference.

Implementation Method 1

A modulated backscatter response reflects from the digital circuit upon arrival of the incident carrier wave in the presence of the switching operations

Methodology Applied
Scientific EffectBackscattering: Reflection

Implementation Method 2

A detection device is positioned to receive the modulated backscatter response

Methodology Applied
Scientific EffectElectromagnetic radiation detection: Electromagnetic Induction

Data Source

PatentEP3912067B1System and method for detecting hardware trojan circuits
Publication Date: 2025.08.20 GEORGIA TECH RES CORP
  • EP3912067B1 patent drawingFigure 1
  • EP3912067B1 patent drawingFigure 2A~2C
  • EP3912067B1 patent drawingFigure 3

AI summary

A system for detecting hardware Trojans in a computerized device includes a digital circuit having switching components operating pursuant to at least one clock frequency and positioned within an interrogation range of an incident carrier wave. A modulated backscatter response is reflected from the digital circuit upon arrival of the incident carrier wave in the presence of the switching operations. A detection device is positioned to receive the modulated backscatter response. A computer connected to the detection device identifies harmonics of a respective clock frequency of the digital circuit from the backscatter response and identifies characteristics of the harmonics indicating a presence or an absence of a hardware Trojan connected to the digital circuit.