Physically Unclonable Function Device Using Heterogeneous Media
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Solution Overview
Problem
Current Physically Unclonable Function (PUF) devices lack sufficient entropy and can be easily modeled or measured, making them inadequate for secure key generation and storage.
Innovation Solution
The proposed PUF device utilizes a complex interaction of multiple conducting paths embedded within a heterogeneous media, with modulated signal frequencies, phases, and amplitudes to generate a unique and unpredictable response, making it difficult to clone or model.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing PUF devices exploit manufacturing differences between identical silicon circuits, then device identification is achieved, but sufficient entropy is not provided for true unclonability
Solution Approach 1:
The patent changes the physical parameters being exploited from standard silicon manufacturing variations to electromagnetic field interactions in heterogeneous media. By using media with different electrical, magnetic, and dielectric properties (conductivity, permeability, permittivity), the system achieves higher entropy and true unclonability while maintaining the PUF function of generating unique device identifiers.
2Reliability
If alternative PUF types are used to increase entropy, then unclonability is improved, but external read-out circuitry is required and black-box attacks become vulnerable
Solution Approach 1:
The PUF device performs self-characterization by using its own internal electromagnetic field interactions to generate its unique response. The heterogeneous media and conducting paths within the device create inherent physical differences that automatically provide the unclonable characteristics without requiring external read-out circuitry or complex measurement systems, thereby eliminating vulnerability to black-box attacks.
3Reliability
If cryptographic keys are stored in non-volatile digital memory with countermeasures, then key protection is achieved, but the system becomes difficult and expensive to implement
Solution Approach 1:
The patent extracts the key generation function from traditional cryptographic storage systems and embeds it directly in the physical structure of the PUF device. By generating keys through the inherent electromagnetic field interactions of the heterogeneous media and conducting paths, the system eliminates the need for separate secure storage mechanisms, reducing implementation complexity and cost while maintaining key protection.
4Reliability
If multiple conducting paths interact within heterogeneous media, then the number of Challenge-Response pairs increases and security is enhanced, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating heterogeneous media with spatially varying electrical, magnetic, and dielectric properties. Different regions of the media have different characteristics (conductivity, permeability, permittivity), which creates complex electromagnetic field interactions between conducting paths. This local variation in material properties generates the high entropy and unique responses needed for security without requiring complex external control systems.
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 results in a PUF device with a large number of Challenge-Response pairs, enhanced security against invasive attacks, and improved resistance to modeling and cloning, effectively addressing the limitations of existing PUF technologies.
Implementation Method 1
there exists a complex electrical and magnetic coupling between each permutation of the conducting paths
Data Source
AI summary
A physically unclonable function (PUF) device 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 a portion of each of the conductors, and circuitry applys an electrical challenge signal to at least one of the conductors and for receiving 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.