Magnetic Sensor Array for PUF Authentication
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Solution Overview
Problem
Current magnetic PUF authentication systems face challenges in accurately and efficiently measuring the complex magnetic fields of non-rotating PUFs, leading to potential false positives and negatives, especially with smaller or larger PUF tags, which can compromise security and increase the risk of counterfeiting in critical industries.
Innovation Solution
A multi-axis magnetic sensor array with increased two-dimensional spatial resolution and a calibration system to ensure accurate placement of sensors, combined with a verification algorithm like the Pearson Correlation Function, to enhance measurement accuracy and reliability, reducing the likelihood of false positives and negatives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single magnetic sensor is used to measure the magnetic field of a non-rotating PUF, then the device complexity is reduced, but the measurement precision and spatial resolution are insufficient leading to false positives and negatives
Solution Approach 1:
The patent divides the measurement task into multiple segments by using an array of multiple magnetic sensors instead of a single sensor. Each sensor measures the magnetic field at a specific location, and the combined data from all sensors provides high-resolution spatial mapping of the magnetic fingerprint. This segmentation approach enables accurate authentication while maintaining manageable system complexity through modular sensor design.
2Measurement precision
If multiple magnetic sensors are arranged in a dense array to achieve high spatial resolution, then the measurement accuracy improves, but the manufacturing precision requirements and placement accuracy become more stringent
Solution Approach 1:
The patent implements self-calibration functionality where the system automatically determines the relative positions and sensitivity characteristics of each sensor in the array during operation. By using reference measurements and mathematical algorithms, the system compensates for manufacturing tolerances and placement variations, eliminating the need for extremely precise manual positioning while maintaining high measurement accuracy.
3Measurement precision
If the sensor array is placed closer to the PUF surface to capture stronger magnetic signals, then the measurement sensitivity increases, but the risk of sensor damage and contamination increases
Solution Approach 1:
The patent introduces a non-magnetic spacer or support structure as an intermediary between the magnetic sensors and the PUF surface. This intermediary maintains a controlled, optimized distance that is close enough to capture strong magnetic signals for accurate detection but far enough to protect sensors from physical damage, contamination, and wear during repeated authentication operations.
4Reliability
If a large number of sensors are used to cover the entire PUF surface, then the authentication reliability increases, but the cost and device complexity increase significantly
Solution Approach 1:
The patent applies local quality by concentrating sensor measurements in regions where the magnetic fingerprint contains the most discriminative information. Rather than uniformly distributing sensors across the entire PUF surface, the system identifies and focuses measurement resources on critical areas that provide the highest authentication reliability, reducing the total number of sensors needed while maintaining or improving authentication accuracy.
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 significantly improves the measurement accuracy and reliability of magnetic fields across PUF surfaces, reducing the risk of counterfeiting by increasing the confidence level in authenticating genuine PUFs and enhancing security through higher spatial resolution and precise sensor placement.
Implementation Method 1
a PUF that contains magnetic particles, which generate a complex magnetic field near the surface of the PUF part. This magnetic field may be measured along a path and data corresponding to the magnetic field components recorded
Data Source
AI summary
A magnetic sensor array device is described that is constructed with multiple single sensor die, diced out of a wafer as a group and packaged in a wafer level package (WLP). The device comprises an array of multi-axis magnetic sensors that can measure the multi-dimensional magnetic field of an arbitrary sized two-dimensional region with high spatial resolution, reduced sensing distance, higher measurement throughput, tolerance to motion, improved temperature measurement, and improved yield when placed on a circuit card comprises part of an authentication system including a physical unclonable function (“PUF”), a substrate, a plurality of magnetized particles randomly dispersed in the substrate, and a PUF reader constructed using one or more of the magnetic sensor array devices wherein the PUF reader measures the magnetic field at multiple locations in close proximity to the magnetized particles. The measured magnetic field data may be compared to previously enrolled data to assess authenticity.