Multilayer PCB with Random Conductive Patterns for Key Protection
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Solution Overview
Problem
Current tamper-resistant security products for cryptographic keys and codes in computers and telecommunication systems are difficult to manufacture, expensive, and prone to defects such as bowing, air bubbles, and polymer film issues during assembly, leading to erroneous calls and manufacturing failures.
Innovation Solution
A multilayered electronic package structure with undetectable conductive materials embedded in a random pattern within the printed circuit board, utilizing 3D interlayer connections and laser-drilled holes filled with conductive pastes, and featuring a complex matrix of resistive networks without copper pads, providing enhanced protection against tampering attempts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional tamper-resistant security products are used for cryptographic keys and codes, then security protection is provided, but manufacturing becomes difficult and expensive with defects such as bowing, air bubbles, and polymer film issues
Solution Approach 1:
The security structure is divided into multiple functional layers including PCB substrate layer, conductive material layer with random pattern, 3D interlayer connections, laser-drilled holes with conductive paste, and resistive network layer without copper pads. Each layer performs a specific security function, making the overall structure more reliable while enabling standardized manufacturing processes for each segment
Solution Approach 2:
Different regions of the PCB have different properties: undetectable conductive materials are embedded in random patterns in specific areas, 3D interlayer connections are placed at critical security points, and resistive networks are configured without copper pads in sensitive zones. This localized differentiation enhances security where needed while maintaining manufacturability
2Reliability
If complex multilayered security structures are implemented, then tamper resistance is improved, but manufacturing precision requirements increase due to laser-drilled holes and conductive paste filling
Solution Approach 1:
The laser-drilled holes are filled with conductive paste that self-aligns and cures to create electrical connections. The random pattern of undetectable conductive materials provides inherent tamper detection without requiring precise alignment during manufacturing. This self-service approach reduces the precision burden on manufacturing equipment while maintaining high tamper resistance
Solution Approach 2:
Traditional planar connections are replaced with 3D interlayer connections that extend vertically through the PCB layers. Laser-drilled holes provide three-dimensional pathways for conductive paste to create connections between layers, adding a vertical dimension that enhances security while using standard PCB manufacturing capabilities
3Difficulty of detecting and measuring
If undetectable conductive materials are embedded in random patterns, then detection of tampering attempts becomes more difficult, but device complexity increases
Solution Approach 1:
The conductive materials are arranged in asymmetric random patterns rather than symmetric or regular grids. This asymmetry makes it extremely difficult for tamperers to predict or detect the pattern using conventional inspection methods, while the randomness itself can be generated using standard PCB design tools, limiting the increase in device complexity
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 achieves a higher degree of reliability and cost-effectiveness by making tampering attempts extremely difficult, allowing for pre-assembly testing and ensuring the security of cryptographic keys and codes, while being compatible with standard PCB production processes.
Implementation Method 1
laser-drilled holes filled with conductive pastes
Data Source
AI summary
An arrangement for the protection of cryptographic keys and codes from being compromised by external tampering, wherein the arrangement is utilized within a multilayered securing structure. More particularly, there is provided a multilayered securing structure for the protection of cryptographic keys and codes, which may be subject to potential tampering when employed in computers and/or telecommunication systems. A method is provided for producing such multilayered securing structures within a modular substrate with the intent to protect cryptographic keys and codes which are employed in computers and/or telecommunication systems from the dangers of potential tampering or unauthorized access.