Random Security Circuit Patterns for In-Situ Tamper Sensors
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Solution Overview
Problem
Existing tamper-proof electronic assemblies are susceptible to tampering and reverse engineering due to the potential for adhesive-induced cavities and the need for physical handling during assembly, which compromises security and yield.
Innovation Solution
A method for generating a random security circuit pattern in-situ on the surface of an enclosure, using a trace pattern that extends through nodes and is randomly modified to achieve a desired randomization index, facilitating the fabrication of a tamper-respondent sensor without adhesive, thereby enhancing security and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive is used to assemble the tamper-respondent sensor onto the enclosure, then the sensor can be attached to the enclosure surface, but adhesive-induced cavities may be formed and physical handling is required, which compromises security and yield
Solution Approach 1:
The patent merges the sensor fabrication process with the enclosure manufacturing process by forming the security circuit directly on the enclosure surface during the same manufacturing cycle. This integration eliminates the need for separate adhesive assembly and physical handling operations, thereby maintaining security while enabling manufacturing.
Solution Approach 2:
The security circuit is fabricated in advance as part of the enclosure manufacturing process itself, before the enclosure is completed. The circuit is formed directly on the enclosure surface during the molding or manufacturing cycle, so that when the enclosure is assembled, the sensor is already integrated and requires no additional attachment steps.
2Ease of manufacture
If a fixed security circuit pattern is used, then fabrication is simpler, but the assembly is susceptible to reverse engineering and tampering
Solution Approach 1:
The patent implements a dynamic randomization process where the security circuit pattern is randomly generated for each production cycle. The circuit traces are formed by randomly selecting paths through a grid of nodes, ensuring that no two enclosures have identical patterns. This dynamic variation prevents reverse engineering while the automated generation process maintains manufacturing simplicity.
Solution Approach 2:
The patent changes the spatial parameters of the security circuit by randomly varying the trace paths, node connections, and circuit geometry for each enclosure. This parameter randomization transforms the circuit from a fixed, predictable pattern to a unique, unpredictable configuration that resists tampering and reverse engineering while being generated through automated processes.
3Adaptability or versatility
If the tamper-respondent sensor is formed separately and then assembled to the enclosure, then the sensor can be manufactured independently, but physical handling during assembly reduces yield and compromises security
Solution Approach 1:
The patent combines the sensor fabrication and enclosure manufacturing into a single integrated process. The security circuit is formed directly on the enclosure surface during the enclosure's manufacturing cycle, eliminating the need for separate sensor production and subsequent assembly operations. This merger maintains manufacturing flexibility while dramatically improving yield by eliminating handling steps.
4Reliability
If multiple layers of security circuit are fabricated, then reverse engineering becomes more difficult, but the fabrication process becomes more complex
Solution Approach 1:
The patent segments the security circuit into multiple layers stacked on the enclosure surface. Each layer contains randomized trace patterns that must all be compromised for successful tampering. The layered structure increases security against reverse engineering while the automated layering process manages fabrication complexity through systematic repetition of the randomization algorithm for each layer.
Data Source
AI summary
In-situ fabrication of tamper-respondent sensors with random security circuit patterns is provided. The method includes establishing a random security circuit pattern for fabricating a security circuit of a tamper-respondent sensor to enclose, at least in part, one or more components within a secure volume. The establishing includes generating a trace pattern extending once through nodes of a plurality of nodes dispersed within an area of the tamper-respondent sensor, and randomly modifying the trace pattern to produce a randomly modified trace pattern with a desired randomization index relative to a specified randomization threshold, and providing the randomly modified trace pattern as a random security circuit pattern. Further, the method includes initiating fabricating of the tamper-respondent sensor in-situ on a surface of an enclosure to facilitate defining the secure volume, with the fabricating using the random security circuit pattern.