Composite PUF Security Marking for Anti-Counterfeit Verification

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Solution Overview

Problem

Existing anti-counterfeiting methods for physical objects lack an effective way to verify authenticity and protect against tampering using a physical unclonable function (PUF) that is both secure and versatile.

Innovation Solution

A composite security marking comprising a PUF and a digital signature, where the PUF's response is cryptographically signed, providing a challenge-response authentication scheme to verify authenticity, enhanced by up-converting dyes or microstructures, and a pointer for digital signature access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a PUF is used for anti-counterfeiting, then security against counterfeiting is improved, but verification complexity increases

Engineering Contradiction:
Improvesecurity against counterfeitingVSAvoidverification complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A reader device serves as an intermediary between the PUF-marked product and the verification system. The reader device applies challenges to the PUF, captures responses, and performs cryptographic verification, simplifying the overall verification process while maintaining high security standards.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The PUF is applied to the product during manufacturing as a preliminary security measure. The challenge-response pairs are pre-established, and the digital signature is created in advance, enabling efficient verification later without complex real-time computations.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a digital signature is added to the PUF response, then authentication security is improved, but data processing complexity increases

Engineering Contradiction:
Improveauthentication securityVSAvoiddata processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical verification systems with cryptographic methods. Digital signatures and cryptographic hash functions are used to authenticate PUF responses, providing strong security with simpler implementation compared to traditional physical verification mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transforms the PUF response into a cryptographic hash value, changing the parameter representation from raw physical response to a fixed-size hash. This enables efficient digital signature application and verification while maintaining the unique characteristics of the PUF.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If up-converting dyes or microstructures are used to enhance the PUF, then security against cloning is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvesecurity against cloningVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses composite security markings that combine PUF with up-converting dyes or microstructures. These composite materials provide enhanced security against cloning while maintaining compatibility with existing manufacturing processes through integrated application methods.

Inventive Principle:
Principle #40Composite materials

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 composite security marking significantly enhances the security level against counterfeiting and tampering by ensuring authenticity verification through a robust cryptographic hash comparison, making it virtually impossible to clone the PUF's response.

Implementation Method 1

enhanced by up-converting dyes or microstructures

Methodology Applied
Scientific EffectUp-conversion:

Data Source

PatentEP3640923B1PUF based composite security marking for Anti-counterfeiting
Publication Date: 2026.01.21 MERCK PATENT GMBH
  • EP3640923B1 patent drawingFigure 1(a)~1(f)
  • EP3640923B1 patent drawingFigure 2
  • EP3640923B1 patent drawingFigure 3

AI summary

The present invention relates to a method of reading with a reader device a marking comprising a physical unclonable function, PUF, and a corresponding reader device. The method comprises a stimulation step, wherein a physical challenge according to a predetermined challenge-response authentication scheme corresponding to the PUF is created and applied to a PUF; a detection step, wherein a response generated by the PUF in accordance with the challenge-response authentication scheme in reaction to the challenge is detected and a digital signal representing the response is generated; a processing step, wherein the digital signal is processed in order to generate a hash value of the response by application of a predetermined cryptographic hash function to the digital signal; an output step, wherein data representing the generated hash value as a first reading result is output; a communication step, wherein the first reading result is communicated over a communication link to an opposing side, wherein the communication step further comprises capturing and sending security-related information to a predetermined opposing side over the communication link; and an information monitoring step, wherein a security event is detected in information contained in a signal received from the opposing side over the communication link.