Magnetometer Chip Array for Magnetic PUF Authentication
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Solution Overview
Problem
Current magnetic PUF reader systems for non-rotating objects require multiple sensors or movement to accurately sample magnetic fingerprints, leading to high probabilities of false positives, which can be exploited by counterfeiters, and existing solutions do not provide sufficient confidence in authentication.
Innovation Solution
A low-cost PUF fingerprint reader is developed using a dense array of discrete 3-axis magnetometer chips with sensors spaced approximately 1 mm apart, and a calibration method involving X-raying or a calibration fixture to ensure accurate sensor placement, along with a correlation algorithm to validate readings, increasing the number of sensors or using mechanical movement to enhance authentication confidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple discrete magnetometer chips are used to sample magnetic fingerprint at multiple locations, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the sensing task into multiple discrete 3-axis magnetometer chips arranged in an array, with each chip sampling at a specific location. This segmentation allows comprehensive coverage of the magnetic fingerprint across multiple points, improving measurement precision while maintaining manageable complexity through modular design
Solution Approach 2:
The patent transitions from single-point measurement to multi-point spatial sampling by arranging magnetometer chips in a two-dimensional array pattern. This dimensional expansion enables sampling across the surface area of the PUF, capturing spatial variations in the magnetic field that enhance authentication reliability
2Reliability
If sensors are spaced further apart to reduce false positives, then authentication reliability is improved, but measurement precision deteriorates
Solution Approach 1:
The patent optimizes the spacing parameter between magnetometer chips to achieve an optimal balance. By carefully selecting the distance between sensors, the system captures sufficient spatial detail for reliable authentication while maintaining adequate sampling resolution to accurately characterize the magnetic fingerprint
Solution Approach 2:
The patent employs more sensors than the absolute minimum required, creating a denser sampling array than strictly necessary. This excessive sampling provides redundant measurements that improve reliability by making it harder for counterfeiters to replicate the fingerprint, while the additional sensors are distributed sparsely enough to avoid excessive complexity
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 reduces the probability of false positives, providing a high confidence level in authenticating magnetic PUFs, making counterfeiting costly and impractical, while maintaining a low-cost and efficient authentication process.
Implementation Method 1
A low cost PUF fingerprint reader can be constructed using multiple discrete 3-axis magnetometer chips
Data Source
AI summary
A system for use in authentication processes is described comprising a physical unclonable function (“PUF”), a substrate, a plurality of magnetized particles randomly dispersed in the substrate, a PUF reader constructed using multiple discrete magnetometer chips that have magnetic field sensors, placed on a circuit card in an array with a sufficient center to center spacing between sensing elements of adjacent magnetometer chips, wherein the PUF reader measures the magnetic field data 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.