Phase-Change Capacitor PUF for Wider Randomness Bandwidth

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Solution Overview

Problem

Existing capacitance-based physical unclonable functions have limited bandwidth in randomness, making them vulnerable to hacking and data breaches.

Innovation Solution

Incorporating phase changeable materials in the dielectric medium of capacitors that change conductivity between crystalline and amorphous states, altering the capacitance value unpredictably based on local surroundings, enhancing the randomness and security of the physical unclonable function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a capacitor with conducting particles dispersed in dielectric medium is used as physical unclonable function, then the device can be easily embedded in a chip, but the bandwidth within which the randomness of the capacitance varies is relatively limited

Engineering Contradiction:
Improveease of embedding in chipVSAvoidbandwidth of randomness
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by introducing phase changeable materials that can switch between crystalline and amorphous states, fundamentally altering the conductivity parameter of conducting particles. This enables the physical unclonable function to generate a wider range of capacitance values by controlling the structural state of particles, thereby expanding the randomness bandwidth while maintaining chip embeddability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining phase changeable materials (such as chalcogenide glasses) with conducting particles and dielectric media. This composite structure allows the system to exhibit multiple states (crystalline/amorphous) with different conductivity properties, enabling enhanced randomness bandwidth while maintaining the compact capacitor structure suitable for chip integration

Inventive Principle:
Principle #40Composite materials

2Device complexity

If the dielectric medium contains conducting particles with fixed structural state, then the capacitor structure is simple, but the randomness and predictability of capacitance values are limited

Engineering Contradiction:
Improvestructure simplicityVSAvoidrandomness and security
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies dynamics by making the conducting particles' structural state changeable rather than fixed. The phase changeable materials can dynamically switch between crystalline and amorphous states in response to thermal or electrical stimuli, creating a dynamic physical unclonable function that generates unpredictable capacitance values while maintaining a relatively simple capacitor structure

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent directly applies phase transitions by utilizing materials that can reversibly change between crystalline and amorphous phases. These phase transitions result in significant changes in conductivity, enabling the capacitor to produce a wide range of random capacitance values. The phase changeable materials are integrated into the conducting particles within the dielectric medium, maintaining structural simplicity while dramatically enhancing randomness and security

Inventive Principle:
Principle #36Phase transitions

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

Significantly increases the randomness and bandwidth of capacitance values, providing enhanced security against unauthorized access and data breaches by making the capacitance distribution highly unpredictable.

Implementation Method 1

the conducting particles comprising a phase changeable material being changeable between a first structural state having a first conductivity and a second structural state having a second conductivity different from the first conductivity

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

the physical unclonable function comprising a capacitor comprising a dielectric medium being arranged at least partially between the electrodes of the capacitor and being configured for contributing to a capacitance value of the capacitor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2337263A1Token comprising improved physical unclonable function
Publication Date: 2011.06.22 NXP BV
  • EP2337263A1 patent drawingFigure 1A~1B
  • EP2337263A1 patent drawingFigure 1C~1D
  • EP2337263A1 patent drawingFigure 2

AI summary

The invention relates to a token (100), to an integrated circuit (200) comprising the token, to a method of randomizing the token and a system (500, 502) for randomizing the token. The token comprises a physical unclonable function (10, 12, 14, 16, 18) and comprising probing means (110) for probing the physical unclonable function. The physical unclonable function comprises a capacitor (20, 22) comprising a dielectric medium (30, 32) being arranged at least partially between the electrodes (20A, 20C; 22A, 22C) of the capacitor. The dielectric medium is configured for contributing to a capacitance value of the capacitor and comprises conducting particles (40, 42; 40A, 40B, 40C) substantially randomly dispersed in the dielectric medium. The conducting particles comprise a phase changeable material being changeable between a first structural state (40A, 40C) having a first conductivity and a second structural state (40B) having a second conductivity different from the first conductivity.