PCB Venting Channels for Pressure-Equalized Tamper Enclosures
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Solution Overview
Problem
FIPS-4 compliant cryptographic modules face challenges in maintaining an isobaric environment within sealed enclosures, leading to false tamper detection and mechanical deformation risks due to pressure differences, which can compromise security sensors.
Innovation Solution
An integrated venting system is implemented in a printed circuit board (PCB) with at least three interconnected VIA channels, spanning through different planar levels to maintain equilibrium pressure and prevent tampering, while ensuring the venting system does not interfere with embedded logic or the functionality of the PCB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PCB is enclosed within a sealed protective sleeve to prevent tampering, then security protection is improved, but pressure differences cause false tamper detection and mechanical deformation
Solution Approach 1:
A pressure equalization channel is introduced as an intermediary element between the sealed enclosure and the external environment. This channel allows pressure to equalize across the enclosure walls, eliminating the harmful pressure differential that causes false tamper detection and mechanical deformation, while the sealed enclosure continues to provide security protection against unauthorized access
Solution Approach 2:
The pressure equalization function is extracted from the sealed enclosure system by creating a separate venting pathway through the PCB. This allows the enclosure to maintain its sealed protective function while the extracted pressure equalization capability prevents the harmful effects of pressure differences
2Reliability
If pressure equalization vents are added to the PCB, then false tamper detection is reduced, but the PCB structure becomes more complex
Solution Approach 1:
The pressure equalization venting system is merged with the existing PCB structure by forming channels through the PCB substrate itself. The venting channels are integrated into the PCB manufacturing process, combining the structural and venting functions into a single unified component, thereby minimizing additional complexity
Solution Approach 2:
The PCB serves multiple functions: it provides structural support for electronic components, establishes electrical connections through traces and vias, and simultaneously acts as the pressure equalization system through integrated venting channels. This multi-functionality reduces the need for separate venting components, thereby 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 integrated venting system effectively mitigates false tamper detection and mechanical deformation risks, enhancing the security and reliability of FIPS-4 compliant cryptographic modules by maintaining an isobaric environment and preventing unauthorized access.
Implementation Method 1
The integrated venting system functions to maintain an isobaric environment between a portion of the PCB that is housed within the enclosure and atmospheric pressure
Data Source
AI summary
The embodiments relate to a method for integrating a venting system in a circuit board. Three or more interconnected accesses (VIAs) are formed in a printed circuit board (PCB). The VIAs are interconnected by routing a bi-planar channel spanning through the VIAs. The channel includes at least two sections, including a first channel section at a first plane extending from the first VIA to the second VIA and a second channel section at a second plane extending from the second VIA to the third VIA. The first and second sections are at different planar levels.