Optical Channel Data-Leak Detection With Spectral Entropy

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Solution Overview

Problem

Existing cybersecurity measures struggle to detect and localize data leaks through optical channels, which are challenging to identify due to their ability to blend with ambient light and are a significant threat to secure networks.

Innovation Solution

A method and system that utilize spectral analysis to detect and localize optical data leaks by capturing video clips, applying fast Fourier transforms, filtering out strong tones, and identifying areas of high spectral entropy using a bandpass filter to highlight suspect transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If spectral analysis methods are used to detect optical data leaks, then detection precision is improved, but device complexity increases

Engineering Contradiction:
Improvedetection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the video feed into multiple blocks and applies FFT analysis to each block independently. This segmentation allows the system to achieve high detection precision by analyzing spectral characteristics of individual regions while keeping the overall computational complexity manageable through parallel processing of divided segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts only the spectral entropy metric from the full FFT analysis results, focusing computation on the specific feature (spectral entropy) that indicates data leaks. This extraction approach maintains high detection precision by concentrating on relevant spectral characteristics while reducing the complexity of processing entire frequency spectra.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If bandpass filtering is applied to eliminate strong tones, then detection precision is improved, but processing time increases

Engineering Contradiction:
Improvedetection precisionVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies bandpass filtering as a preliminary step before spectral entropy calculation to remove known strong tones (power line frequencies, camera refresh rates). This preliminary action improves subsequent detection precision by eliminating dominant frequencies that would otherwise mask weaker data leak signals, while the filtering is optimized to minimize processing overhead.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If video clips are subdivided into smaller blocks, then detection precision is improved, but computational complexity increases

Engineering Contradiction:
Improvedetection precisionVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent subdivides video frames into blocks and applies FFT to each block, enabling precise localization of optical data leaks to specific regions. The segmentation improves detection precision by allowing block-by-block spectral analysis while managing computational complexity through efficient memory access patterns and potential parallel processing of independent blocks.

Inventive Principle:
Principle #1Segmentation

4Productivity

If near-real-time detection is implemented, then productivity is improved, but measurement precision may deteriorate

Engineering Contradiction:
Improvedetection speedVSAvoiddetection precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies bandpass filtering to eliminate only the most prominent strong tones rather than performing complete spectral subtraction or advanced adaptive filtering. This partial action approach maintains near-real-time processing speed while sufficiently improving detection precision by removing the dominant interfering frequencies that would otherwise obscure data leak signals.

Inventive Principle:
Principle #16Partial or excessive 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

Enables near-real-time detection and localization of optical data leaks, allowing cybersecurity professionals to mitigate the threat of out-of-band optical channels effectively and cost-effectively using commodity hardware.

Implementation Method 1

applying a fast Fourier transform to each of the video clips to generate a corresponding frequency domain representation

Methodology Applied
Scientific EffectFast Fourier Transform:

Implementation Method 2

applying a bandpass filter to each of the frequency domain representations to eliminate strong tones present throughout the video clips

Methodology Applied
Scientific EffectBandpass filtering: Filter (electronic)

Data Source

PatentUS12452280B2Method and system of detecting computer network data leaks over optical channels
Publication Date: 2025.10.21 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES
  • US12452280B2 patent drawing
  • US12452280B2 patent drawing
  • US12452280B2 patent drawing

AI summary

A method and system for detecting computer network data leaks over optical channels, for example using a mobile phone or other handheld device to rapidly scan a room with many light sources to identify the hidden transmission of data via optical steganography. The method of identification leverages spectral divergence created by the entropy produced by steganographically embedding data in the optical channel. The method and system proceed through multiple steps that can be computed in near real-time to eliminate background spectrum effects and isolate likely sources of information. The user or automated detection system captures a short video, and the video frames are then subdivided into smaller blocks effectively producing many adjacent videos of smaller pixel area.