Tamper Sensing Encapsulant with Shape Actuation Layers
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Solution Overview
Problem
Current cryptographic modules lack an effective physical security mechanism to detect and respond to unauthorized attempts at physical access, as they do not provide a complete envelope of protection.
Innovation Solution
A tamper sensing encapsulant with shape actuation layers is used to form a circuit upon thermal loading, which disables the cryptographic module by creating a short circuit between trace elements, thereby providing immediate zeroization and permanent disablement of sensitive data storage components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complete envelope of protection is provided around the cryptographic module, then security against unauthorized physical access is improved, but device complexity increases
Solution Approach 1:
The patent implements multiple encapsulant layers nested around the cryptographic module, with each layer containing trace elements that respond to different tamper conditions. The first encapsulant layer contains trace elements responsive to mechanical stress, while the second layer contains trace elements responsive to thermal conditions, creating a nested security envelope that detects various unauthorized access methods.
Solution Approach 2:
The patent utilizes shape actuation layers that change their physical state in response to thermal parameters. When exposed to extreme temperatures, the shape actuation layer transforms, causing trace elements to contact and form conductive paths that indicate tampering. This parameter-based response mechanism enhances security detection without requiring complex active sensing systems.
2Measurement precision
If tamper detection sensitivity is increased to detect all unauthorized attempts, then security detection capability is improved, but false positive rate increases
Solution Approach 1:
The patent divides the tamper detection system into multiple independent encapsulant layers, each with trace elements that respond to specific tamper conditions. The first encapsulant layer detects mechanical stress through its trace elements, while the second encapsulant layer detects thermal tampering through shape actuation layers. This segmentation allows the system to distinguish between different types of unauthorized access attempts, reducing false positives while maintaining high detection sensitivity.
Solution Approach 2:
The shape actuation layer serves as an intermediary between the thermal environment and the trace elements. It transforms thermal energy into mechanical displacement, causing trace elements to contact only when specific thermal thresholds are exceeded. This intermediary mechanism provides a controlled response that reduces false positives while maintaining detection sensitivity for genuine tamper attempts.
3Reliability
If multiple encapsulant layers with shape actuation layers are used, then tamper detection capability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs thin film encapsulant layers with integrated shape actuation properties. These flexible thin films can be deposited and patterned using standard semiconductor fabrication techniques, allowing multiple layers to be manufactured sequentially. The trace elements are formed as conductive patterns within or on the thin film layers, enabling complex multi-layer structures to be fabricated through repeated cycles of deposition, patterning, and lamination rather than requiring complex assembly processes.
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 effectively forms a complete envelope of protection around the cryptographic module, detecting and responding to unauthorized access attempts by immediately disabling the module upon detection of unauthorized physical access, ensuring secure storage of sensitive data.
Implementation Method 1
The first shape actuation layer is positioned against the second shape actuation layer such that the first trace element and the second trace element do not physically touch at a predetermined operational temperature and do physically touch when the first shape actuation layer and the second shape actuation layer are thermally loaded
Data Source
AI summary
To provide for a physical security mechanism that forms a complete envelope of protection around the cryptographic module to detect and respond to an unauthorized attempt at physical access, a tamper sensing encapsulant generally encapsulates the cryptographic module. The tamper sensing encapsulant includes a first shape actuation layer associated with an electrically conductive first trace element and a second shape actuation layer associated with an electrically conductive second trace element. The first shape actuation layer is positioned against the second shape actuation layer such that the first trace element and the second trace element do not physically touch at an operating temperature of the cryptographic module and do physically touch when the first shape actuation layer and the second shape actuation layer are thermally loaded. Upon first trace element and the second trace element touching, a circuit is formed that disables the cryptographic module.