Identity Card Physical Unclonable Function with Varying Light Reflectivity
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Solution Overview
Problem
Current identity cards lack effective implementation of Physical Unclonable Functions (PUFs) that provide inherent unclonability and tamper resistance, which are essential for high-end security architectures.
Innovation Solution
The integration of a physical unclonable function within the identity card using a structure with varying light reflectivities, comprising a first and second arrangement of light reflecting elements with different reflectivities, and an optical sensor to sense the reflected light, forming a unique optical fingerprint or cryptographic key.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PUF structures with uniform reflectivity are used, then the manufacturing process is simpler, but the sensitivity of optical sensing is insufficient
Solution Approach 1:
The patent applies local quality by creating PUF structures with spatially varying reflectivity properties. Different regions of the PUF structure have different reflectivity values, allowing optimization of light scattering in specific areas to enhance optical sensing sensitivity while maintaining manufacturability through localized rather than global complexity
Solution Approach 2:
The patent changes the optical parameter of reflectivity across different regions of the PUF structure. By varying the reflectivity parameter spatially, the system optimizes light scattering characteristics to improve sensitivity of optical sensing without requiring complete redesign of the entire structure
2Reliability
If bare silicon PUFs are used, then the security of the circuit is ensured, but the card itself does not gain tamper resistance
Solution Approach 1:
The patent merges the PUF circuit structure with the card body itself, integrating the security function directly into the physical card substrate. This combination ensures that both the circuit security and the physical card tamper resistance are provided by the same integrated structure, rather than as separate components
Solution Approach 2:
The patent employs composite material structures that combine optical properties with security functions. The PUF structure is formed using composite materials that provide both the necessary optical characteristics for tamper detection and the cryptographic functions for circuit security
3Measurement precision
If PUFs are implemented with optimal light scattering, then the sensitivity is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the PUF structure into multiple regions with different reflectivity characteristics. This segmentation allows each region to be optimized for specific optical functions while maintaining overall manufacturability, as each segment can be produced using standard fabrication techniques rather than requiring a completely new manufacturing process
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
This approach enhances the security of identity cards by providing a unique and unclonable optical fingerprint, resistant to tampering and model-building attacks, while simplifying the manufacturing process and optimizing light scattering for improved sensitivity.
Implementation Method 1
a first arrangement of light reflecting elements being arranged in a first card body area, and a second arrangement of light reflecting elements being arranged in a second card body area, and wherein the first arrangement of light reflecting elements has a higher light reflectivity than the second arrangement of light reflecting elements
Implementation Method 2
an optical sensor for sensing light reflected from the first arrangement of light reflecting elements and the second arrangement of light reflecting elements
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3b
AI summary
The invention relates to an Identity card, comprising a card body (101) and a physical unclonable function (103) arranged within the card body (101), wherein the physical unclonable function (103) comprises a first arrangement of light reflecting elements (105) being arranged in a first card body area (107), and a second arrangement of light reflecting elements (109) being arranged in a second card body area (111), and wherein the first arrangement of light reflecting elements (105) has a higher light reflectivity than the second arrangement of light reflecting elements (109).