Power Line Firewall for Conducted Signal Exfiltration Blocking
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Solution Overview
Problem
Air-gapped computing systems are vulnerable to data exfiltration through their power supply infrastructure, where malicious signals can be extracted from power conductors without direct access to the devices, posing a significant security risk due to the ability to detect and decode electromagnetic emissions.
Innovation Solution
A power line firewall or filter system that cancels or alters electrical signals on power supply conductors and earthing conductors, preventing signal exfiltration by reshaping fundamental and non-fundamental frequency waveforms, and optionally detecting and reporting anomalous signals, deployed between the power source and the computing devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air-gapped systems are physically isolated from communication networks, then data security is improved, but data exfiltration through power supply infrastructure becomes a viable attack vector
Solution Approach 1:
The patent introduces a power line firewall as an intermediary device inserted between the power source and the air-gapped system. This firewall monitors and filters electrical signals on the power conductors, blocking malicious conducted emissions while allowing legitimate power flow. The intermediary device thus protects the air-gapped system without compromising its physical isolation.
Solution Approach 2:
The power line firewall incorporates feedback mechanisms that continuously monitor electrical signals on power conductors for anomalies indicative of data exfiltration attempts. When suspicious patterns are detected, the system responds by blocking the signals and alerting security personnel, creating a closed-loop security mechanism that adapts to threats in real-time.
2Duration of action of stationary object
If power conductors are used to supply power to air-gapped devices, then operational continuity is maintained, but electromagnetic emissions can carry information about system operations
Solution Approach 1:
The patent converts the harmful electromagnetic emissions carried by power conductors into a detectable signal pattern. By analyzing the electrical characteristics of power consumption, the system identifies anomalies that indicate data exfiltration attempts. The same power conductors that potentially carry information leaks are thus transformed into a monitoring channel for detecting and preventing security threats.
3Reliability
If signal filtering is applied to power conductors, then data exfiltration is prevented, but legitimate power transmission may be affected
Solution Approach 1:
The power line firewall applies signal filtering selectively rather than uniformly across all frequency ranges. It targets specific frequency bands and signal patterns characteristic of data exfiltration attempts while allowing the broader power transmission spectrum to pass through unaffected. This localized filtering approach prevents data leaks without disrupting legitimate power delivery to connected devices.
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 prevents data exfiltration by eliminating detectable signals on power lines and ground conductors, reducing the risk of unauthorized data access and maintaining system security without requiring direct contact or complex equipment.
Implementation Method 1
an inductor coupled in series with the conductor, the inductance of which increases when power at frequencies greater than the nominal frequency flows through the conductor
Implementation Method 2
a passive switching device coupled across the conductor on both sides of the inductor, the device closing when the voltage across it reaches a switching threshold
Data Source
AI summary
The disclosed embodiments relate to method and/or device which is effective at cancelling or altering electrical signals or pulses, generated by, for example, digital electronic systems and components, that are induced, reflected or otherwise made present on the mains power supply conductors and/or the earthing or grounding conductor (if present.) The disclosed embodiments cancel these electrical signals thereby providing an effective means of preventing the exfiltration of various data from a computing or similar system by means of power line emissions. The disclosed embodiments may perform this subjugation by: altering the shape of the fundamental current and voltage waveforms and also altering and diminishing any non-fundamental frequency waveforms to a point where they are no longer measurable or detectable; and preventing the communication via inductive coupling of any electrical signals on mains current onto the grounding path or vice versa.