PCB Obfuscation via MEMS Permutation and X-ray Shielding

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Solution Overview

Problem

Printed Circuit Boards (PCBs) are vulnerable to malicious attacks and reverse engineering due to their complex multistep fabrication and larger feature sizes, which are difficult to secure using existing technologies, especially against non-destructive X-ray probing.

Innovation Solution

A multi-layered security framework is provided using micro electro-mechanical systems (MEMS) devices integrated into PCBs through additive manufacturing, which permute and obfuscate connections, making them harder to detect using X-ray simulations, and includes supplemental obfuscation methods like dummy traces and rearranged surface mount devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If PCB connections are made visible for inspection, then manufacturing quality can be verified, but security against reverse engineering is compromised

Engineering Contradiction:

Improveinspection capabilityVSAvoidreverse engineering vulnerability

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent divides the PCB into multiple layers with connections distributed across different planes. Critical connections are routed through intermediate layers and vias, making them segmentable and harder to trace in a single inspection plane, thus balancing inspection capability with security.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes the third dimension (Z-axis) by routing connections through multiple PCB layers and using vertical vias. This dimensional transformation makes connections invisible from top-down X-ray views while maintaining functional connectivity, resolving the contradiction between inspectability and security.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If X-ray probing power is increased to detect hidden connections, then inspection accuracy improves, but destructive damage to the PCB occurs

Engineering Contradiction:

Improveconnection detectabilityVSAvoiddestructive damage

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates security features and obfuscation elements during the initial PCB design and manufacturing phases. Connection routing is planned to naturally obscure critical paths through layer stacking and via placement, eliminating the need for high-power post-manufacturing inspection that would cause damage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the limitation of low-power X-ray (inability to see through thick PCBs) into a security benefit. By designing connections that rely on multi-layer routing rather than surface visibility, the natural shielding effect of PCB materials becomes a protective feature against non-destructive inspection attacks.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If traditional PCB manufacturing is used, then production simplicity is maintained, but security against malicious attacks is insufficient

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidsecurity vulnerability

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent implements security features using standard PCB manufacturing processes and components. The same fabrication equipment, materials, and assembly techniques used for conventional PCBs are employed, but with enhanced routing strategies and layer configurations that provide security without requiring specialized manufacturing capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution significantly enhances the security of PCBs by reducing their detectability under X-ray probing, requiring higher energy sources for successful inspection, thus preventing successful reverse engineering and tampering.

Implementation Method 1

permuting, using a micro electro-mechanical systems (MEMS) device, a first set of connections interconnecting a first component with a second component in the PCB

Methodology Applied

Scientific EffectMEMS device permutation: Microelectromechanical Systems

Implementation Method 2

integrating the MEMS device into the PCB such that the MEMS device covers a second set of connections from an x-ray probe

Methodology Applied

Scientific EffectX-ray blocking: Absorption (EM radiation)

Data Source

PatentUS20240090136A1Printed circuit board obfuscation systems and methods

Publication Date: 2024.03.14 UNIV OF FLORIDA RESEARCH FOUNDATION INC

AI summary

Various embodiments of the present disclosure provide a framework for obfuscation of a printed circuit board (PCB). In one example, an embodiment provides for generating a plurality of connections interconnecting a plurality of components of the PCB using additive manufacturing, permuting, using a micro electro-mechanical systems (MEMS) device, a first set of connections interconnecting a first component with a second component in the PCB, integrating the MEMS device into the PCB such that the MEMS device covers a second set of connections from an x-ray probe, probing the PCB using x-ray simulation, and iteratively adjusting the permutation of the first set of connections and the integration of the MEMS device using a result of the x-ray simulation to reduce the detectability of the first and second connections based on the result of the x-ray simulation.