Smart Card Security Circuit with Self-Adjusting Sensor
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Solution Overview
Problem
Smart cards with security controllers pose a risk after their validity expires, as they can be reprogrammed or reused for illegal purposes due to the high effort and cost associated with blocking them permanently.
Innovation Solution
A circuit arrangement that includes a sensor and configuration memory to detect system or ambient parameters, triggering an alarm and permanently reconfiguring the sensor to block the chip even in normal operating mode, using a misadjustment signal to alter the detection range and prevent further operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor is used to detect system parameters and trigger alarms, then the ability to detect abnormal conditions is improved, but the complexity of the circuit arrangement increases
Solution Approach 1:
The sensor is configured to perform multiple functions: detecting system parameters during normal operation, detecting abnormal conditions, and permanently altering its detection range in response to misadjustment signals. This multi-functionality reduces the need for separate components for each function, thereby managing complexity while improving reliability.
Solution Approach 2:
The sensor's detection range is dynamically altered based on received signals. During normal operation, it operates within a first detection range. Upon receiving a misadjustment signal, it permanently changes its detection range to a second range that does not encompass the first range, ensuring continuous alarm state. This parameter change mechanism allows the same component to adapt its behavior without requiring additional hardware.
2Reliability
If the sensor's detection range is permanently altered to ensure continuous alarm state, then the security blocking capability is improved, but the normal operation capability is worsened
Solution Approach 1:
The system performs preliminary detection during normal operation to verify that the sensor operates correctly within its first detection range. Only after confirming normal operation does the system allow the sensor to be reconfigured to the second detection range. This preliminary action ensures that the sensor is functioning properly before permanently altering its behavior, thereby maintaining operational capability while enabling security blocking.
Solution Approach 2:
The sensor's detection range is made dynamic rather than fixed. It can transition between a first detection range (for normal operation) and a second detection range (for security blocking). This dynamic configuration allows the system to adapt its operational characteristics based on the current state, maintaining both normal operation capability and security blocking capability as needed.
3Reliability
If the sensor is designed to permanently adjust its detection range in response to misadjustment signals, then the prevention of reprogramming is improved, but the device complexity increases
Solution Approach 1:
The sensor is designed to automatically alter its own detection range in response to misadjustment signals without requiring external intervention or complex configuration systems. The sensor performs self-adjustment by permanently changing its detection parameters when it receives the appropriate signal, thereby preventing reprogramming while minimizing the complexity of the overall system.
Data Source
AI summary
A circuit arrangement in whose operational range a system parameter or an ambient parameter lies within a first range. The arrangement includes a node configured to receive a misadjustment signal and a sensor configured to detect the system parameter or the ambient parameter. The sensor is coupled to the node and is configured to detect whether the system parameter or the ambient parameter lies in a predetermined second range. The sensor outputs an alarm signal if the system parameter or the ambient parameter does not lie in the second range, within which the first range lies. The sensor is further configured to permanently adjust the second range in reaction to the misadjustment signal such that the second range does not encompass the first range.