Environment-Dependent PUF Structure for High-Entropy Authentication
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Solution Overview
Problem
Current Physically Unclonable Functions (PUFs) lack sufficient entropy, are vulnerable to attacks, and require external read-out circuitry, making them difficult to use for secure key generation and storage effectively.
Innovation Solution
A PUF device with a complex interaction of conductive paths embedded in a heterogeneous media, allowing for modulated signal frequency, phase, and amplitude, which generates a large number of Challenge-Response pairs and is difficult to model or replicate, incorporating environmental dependencies to enhance security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PUFs exploit manufacturing differences between identical silicon circuits, then device uniqueness is achieved, but entropy is insufficient for true unclonability
Solution Approach 1:
The patent transforms the PUF mechanism from relying on static manufacturing variations to utilizing dynamic environmental parameters (temperature, humidity, pressure, magnetic fields) that continuously modify the electrical characteristics of conductive paths. This parameter transformation enables the system to generate high-entropy responses by challenging the PUF under varying environmental conditions, thereby achieving true unclonability through environmental dependency rather than manufacturing imperfections.
2Ease of operation
If external read-out circuitry is used to measure PUF responses, then response extraction is enabled, but vulnerability to black-box attacks increases
Solution Approach 1:
The patent integrates the read-out circuitry directly within the PUF device structure, merging the challenge application, environmental sensing, and response generation functions into a single self-contained unit. This integration eliminates the need for external read-out circuitry that could be exploited by attackers, while the environmental dependency ensures that even with internal circuitry, the responses cannot be extracted without the specific environmental conditions.
Solution Approach 2:
The patent introduces environmental parameters (temperature, humidity, pressure, magnetic fields) as intermediaries between the challenge input and the response output. These environmental mediators modify the electrical characteristics of conductive paths in unpredictable ways, creating a layer of complexity that prevents direct mapping between challenges and responses, thereby protecting against black-box attacks while enabling response extraction through controlled environmental manipulation.
3Reliability
If PUF response generation is made highly secure through complex physical characteristics, then unclonability improves, but response generation time may become too slow
Solution Approach 1:
The patent employs periodic environmental variations (such as oscillating temperature cycles, alternating magnetic fields, or pressure fluctuations) to modulate the response generation process. By applying periodic challenges that exploit the dynamic response of conductive paths to environmental changes, the system can generate secure responses faster than static measurements would allow, as the periodic action amplifies the signal variations that carry the PUF response information.
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 provides a robust, unclonable key generation and storage system resistant to attacks, with a high number of Challenge-Response pairs and environmental sensitivity, making it suitable for secure authentication and encryption applications.
Implementation Method 1
A physically unclonable function (PUF) device comprising: a plurality of conductors, at least some of which are arranged so that they interact electrically and/or magnetically with one another
Implementation Method 2
a plurality of conductors, at least some of which are arranged so that they interact electrically and/or magnetically with one another
Implementation Method 3
a media surrounding at least a portion of each of the conductors, the media defining at least one cavity, wherein the cavity is structured to provide the device with an environmentally dependent characteristic
Data Source
AI summary
A physically unclonable function (PUF) comprises a plurality of conductors, at least some of which are arranged so that they interact electrically and/or magnetically with one another. A media surrounds at least of portion of each of the conductors and further defines at least one cavity, where the cavity is structured to provide the device with an environmentally dependent characteristic. Circuitry applies an electrical challenge signal to at least one of the conductors and receives an electrical output from at least one of the other conductors to generate an identifying response to the challenge signal that is unique to the device.