Tamper Detection Circuit for Mobile Terminal Case
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Solution Overview
Problem
Conventional mobile terminals are vulnerable to tampering methods that disrupt the case disassembly recognition mechanism, such as injecting conductive liquid onto the tamper detection pattern, which can prevent the detection of disassembly and compromise important data security.
Innovation Solution
A mobile terminal design featuring a tamper detection pattern with multiple conductive and non-conductive areas, a conductive area connection unit, and a conductive area connection detection circuit that maintains electrical connections during assembly and disassembly, and detects tampering attempts by recognizing changes in these connections, including those caused by conductive liquid injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional case disassembly recognition portion with two conductive members is used, then the device can detect case assembly and disassembly, but it becomes vulnerable to tampering with conductive liquid injection
Solution Approach 1:
The tamper detection pattern is segmented into multiple conductive members (first conductive member, second conductive member, and third conductive member) arranged in a specific pattern. This segmentation allows the system to detect not only case disassembly but also conductive liquid injection attempts, as the liquid would create abnormal conductive paths between these segmented elements that differ from the normal moving member contact pattern.
2Device complexity
If the tamper detection pattern uses only two conductive members, then the device structure remains simple, but it cannot detect conductive liquid injection tampering
Solution Approach 1:
The third conductive member is strategically positioned at a specific location relative to the first and second conductive members to create a local quality enhancement in the detection pattern. This local addition provides the capability to detect conductive liquid injection without requiring a complete redesign of the entire detection system, thus balancing complexity and reliability.
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 prevents hacking by accurately detecting tampering attempts, including those using conductive liquid, thereby ensuring the security of important data stored in the mobile terminal.
Implementation Method 1
a conductive area connection unit arranged between the case and the PCB and electrically connecting a part of the conductive areas during assembly of the case and electrically disconnecting the part of the conductive areas during disassembly of the case
Implementation Method 2
The developed tamper method uses conductive liquid. After forming a small hole in the case, conductive liquid is injected onto the tamper detection pattern. When conductive liquid is injected on the tamper detection pattern, the two conductive members separated from each other are electrically connected by the conductive liquid.
Data Source
AI summary
A mobile terminal includes a case capable of being assembled or disassembled, a printed circuit board (PCB) arranged in the case and having a tamper detection pattern, the tamper detection pattern having a plurality of conductive areas and at least one non-conductive area, a conductive area connection unit arranged between the case and the PCB and electrically connecting a part of the conductive areas during assembly of the case and electrically disconnecting the part of the conductive areas during disassembly of the case, and a conductive area connection detection circuit electrically connected to the conductive areas and detecting an electric connection state between the conductive areas. The conductive areas includes a first conductive area, a plurality of second conductive areas arranged to be separated from one another and connected to the first conductive area via the conductive area connection unit, and a third conductive area, at least a part of which is arranged between the second conductive areas.