Tamper-Respondent Assemblies with Trace Regions of Increased Susceptibility
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Solution Overview
Problem
Existing tamper-proof electronic packages face challenges in detecting and responding to unauthorized physical access and environmental fluctuations, particularly in high-security applications where encryption/decryption keys need to be protected from tampering and environmental excursions.
Innovation Solution
A tamper-respondent assembly is designed with a tamper-detect sensor, conductive traces, and an adhesive, configured to create a secure volume around electronic components. The conductive traces form a network that is susceptible to breaking upon tampering, triggering an alarm and erasure of encryption/decryption keys, and are embedded within a multilayer circuit board or electronic enclosure to enhance detection and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductive trace is embedded deeply within the multilayer circuit board to enhance security, then the security protection is improved, but the manufacturing complexity increases
Solution Approach 1:
The circuit board is divided into multiple layers with the conductive trace embedded within the intermediate layers rather than on the surface. This segmentation allows the trace to be protected by surrounding insulating and structural layers, enhancing security while maintaining manufacturability through standard multilayer PCB fabrication processes.
Solution Approach 2:
The conductive trace is nested within the multilayer circuit board structure, surrounded by multiple layers of insulating material and copper planes. This nesting provides enhanced protection against tampering and environmental factors while the overall structure remains compatible with conventional PCB manufacturing techniques.
2Measurement precision
If the tamper-detect sensor is made highly sensitive to detect all tampering attempts, then the detection capability is improved, but the false alarm rate increases
Solution Approach 1:
Different regions of the circuit board are assigned different sensitivity thresholds and detection parameters. Critical areas containing encryption keys have higher sensitivity with lower thresholds, while less critical areas use higher thresholds to reduce false alarms. This localized quality approach optimizes detection capability where needed while minimizing false positives elsewhere.
Solution Approach 2:
The tamper-detection system incorporates feedback mechanisms that analyze detection signals in context, considering factors such as the sequence of events, location of detected changes, and environmental conditions. This feedback processing helps distinguish between genuine tampering attempts and benign environmental fluctuations, reducing false alarm rates while maintaining high detection capability.
Data Source
AI summary
Tamper-respondent assemblies with regions of increased susceptibility to a tamper event are provided, which include one or more tamper-detect sensors, one or more conductive traces, and an adhesive. The tamper-detect sensor(s) facilitates defining a secure volume about one or more electronic components to be protected, and the conductive trace(s) forms, at least in part, a tamper-detect network of the tamper-respondent assembly. The conductive trace(s) is disposed, at least in part, on the tamper-detect sensor(s). The adhesive contacts the conductive trace(s) on the tamper-detect sensor(s), and is disposed, at least in part, between and couples a surface of the tamper-detect sensor(s) to another surface of the assembly. Together, the tamper-detect sensor(s), conductive trace(s), and adhesive are a subassembly, with the subassembly being configured with multiple regions of increased susceptibility to breaking of the conductive trace(s) with a tamper event through the subassembly.