PUF-Based TMR Magnetometer Circuit for IoT Sensor Security
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Solution Overview
Problem
TMR sensors in IoT systems face security threats such as IP core embezzlement, hardware trojan, reverse engineering, and side channel attacks due to limited memory and calculation capacity, making secure data transmission challenging.
Innovation Solution
A PUF-based magnetometer with a safety protection circuit is developed, incorporating a TMR magnetometer main structure, control circuit, column encoder circuit, row encoder circuit, multiplexer, and dynamic comparator. This configuration generates PUF response signals based on random deviations in TMR sensor fabrication, enhancing security by making it difficult for attackers to locate specific sensor positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional encryption techniques such as AES are used in TMR sensors, then data security can be improved, but the device complexity and power consumption increase beyond what the limited memory and calculation capacity of TMR sensors can support
Solution Approach 1:
The patent extracts the encryption function from the TMR sensor itself and implements it externally using a PUF-based system. The TMR sensor array serves only for sensing, while the security functions (key generation, encryption) are performed by separate PUF circuits that exploit manufacturing variations in the TMR sensors to generate unique cryptographic keys without requiring complex encryption circuits within the sensor
Solution Approach 2:
The system uses the inherent manufacturing variations in the TMR sensor fabrication process itself as the source of cryptographic entropy. The PUF circuits read these natural variations to generate unique keys for each sensor array, eliminating the need for external key management infrastructure and reducing overall system complexity
2Measurement precision
If the TMR sensor array is made more sensitive to detect subtle magnetic fields, then measurement precision is improved, but the sensor becomes more vulnerable to side channel attacks and other security threats
Solution Approach 1:
The patent applies preliminary anti-action by implementing security measures before the sensor is deployed or attacked. PUF keys are generated during manufacturing based on inherent fabrication variations, and these keys are used to encrypt data before it leaves the sensor. This preemptive encryption prevents attackers from exploiting the sensor's sensitivity to perform side channel attacks, as the data is already protected
Solution Approach 2:
The PUF-based encryption system acts as an intermediary layer between the sensitive TMR sensor and the external environment. This intermediary encrypts the sensor output using keys derived from manufacturing variations, thereby protecting the sensor from security threats while preserving its measurement precision. The intermediary translates the physical sensor readings into secure cryptographic data
3Reliability
If the internal memory of the TMR sensor is increased to support traditional encryption algorithms, then data security can be improved, but the device complexity and cost increase
Solution Approach 1:
Instead of storing cryptographic keys in the limited internal memory of the TMR sensor, the patent uses the PUF system to dynamically generate keys by reading manufacturing variations from the sensor array itself. This copying approach replaces physical key storage with a key generation process that exploits the unique physical characteristics of each sensor, eliminating the need for large internal memory while maintaining security
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 PUF-based magnetometer effectively resists various security threats, providing high security against IP core embezzlement, hardware trojans, reverse engineering, and side channel attacks, while maintaining functionality as a TMR magnetometer.
Implementation Method 1
TMR sensors have the advantages of high sensitivity, microminiaturization, low cost and low power
Implementation Method 2
the dynamic comparator is used for comparing data input to the positive input terminal and data input to the reverse input terminal to generate a corresponding PUF response signal
Data Source
AI summary
A PUF-based magnetometer with a safety protection circuit is provided. The PUF-based magnetometer includes a TMR magnetometer main structure, a control circuit, a column encoder circuit, a row encoder circuit, a multiplexer and a dynamic comparator. The TMR magnetometer main structure includes n*n TMR sensors, and the TMR magnetometer main structure can also form a PUF circuit together with a control circuit, a column encoder circuit, a row encoder circuit, a multiplexer and a dynamic comparator to realize a function of a TMR magnetometer. The PUF circuit generates PUF response signals based on random deviations of a TMR sensor fabrication process. The PUF response signals generated by the PUF circuit make it more difficult for attackers to locate specific positions of the TPR sensors, and even make it hard to know the existence of the deviations of the TMR sensors.