Secure Embedded Heat Pipe for HSM Thermal Management
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Solution Overview
Problem
Current level 4 compliant Hardware Security Modules (HSMs) face manufacturing complexity and thermal impedance issues due to the use of epoxy material and flex circuits, leading to increased temperature rises and thermal inefficiencies, which compromise the security and performance of cryptographic key management systems.
Innovation Solution
Incorporating a secure embedded heat pipe with 180-degree bends and dead-end traps within the HSM design to directly transfer heat from internal components to the top can, bypassing thermal impedance and enhancing thermal performance while maintaining security features, such as tamper detection and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy material and flex circuits are used in HSM, then security compliance is achieved, but thermal impedance increases and manufacturing complexity increases
Solution Approach 1:
The patent extracts the heat pipe from the traditional external cooling configuration and embeds it directly within the secure region of the HSM. This allows thermal management to be integrated into the security envelope without compromising security compliance, while eliminating the thermal impedance caused by external cooling paths through epoxy and flex circuits.
Solution Approach 2:
The heat pipe acts as an intermediary thermal conduction path between the heat-generating components and the external environment. By using the heat pipe as a dedicated thermal conduit within the secure region, the patent bypasses the high thermal impedance materials (epoxy and flex circuits) that would otherwise be in the thermal path.
2Reliability
If epoxy material and flex circuits are used in HSM, then security compliance is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the thermal management function with the security structure by embedding the heat pipe within the secure region. This integration eliminates the need for separate external cooling paths through complex epoxy and flex circuit assemblies, thereby reducing manufacturing complexity while maintaining FIPS 140 level 4 compliance.
Solution Approach 2:
The encapsulation structure serves multiple functions: it provides security containment, structural support, and now also serves as an integrated thermal management system through the embedded heat pipe. This multi-functionality reduces the need for additional separate components and simplifies manufacturing.
3Temperature
If external heat pipe is used, then thermal performance is improved, but security is compromised due to access through secure region
Solution Approach 1:
The heat pipe is nested within the secure region defined by the encapsulation structure, with its condenser section positioned inside the secure boundary. This nesting ensures that the entire heat pipe, including the portion that contacts external components, is contained within the tamper-resistant envelope, preventing unauthorized access while maintaining thermal performance.
Solution Approach 2:
The patent changes the spatial dimension of the heat pipe integration by embedding it within the secure region rather than positioning it externally. The heat pipe extends vertically through the encapsulation structure, with its evaporator section contacting heat-generating components and its condenser section providing external heat dissipation, all while remaining within the security boundary.
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 embedded heat pipe design improves thermal performance by 13% and supports an additional 5 W of ASIC power, maintaining FIPS 140 level 4 security compliance while simplifying manufacturing and reducing thermal impedance.
Implementation Method 1
A heat pipe is positioned between the top can and the component. The heat pipe includes two or more 180-degree bends.
Implementation Method 2
directly transfer heat from internal components to the top can, bypassing thermal impedance
Data Source
AI summary
Aspects include a cryptographic hardware security module having a secure embedded heat pipe and methods for assembling the same. The cryptographic hardware security module can include a printed circuit board having one or more components. The cryptographic hardware security module can further include an encapsulation structure having a top can and a bottom can. The top can is fixed to a first surface of the printed circuit board and the bottom can is fixed to second surface of the printed circuit board opposite the first surface. A heat pipe is positioned between the top can and the component. The heat pipe includes two or more 180-degree bends. A portion of the heat pipe extends beyond a secure region of the encapsulation structure.