Transponder Authentication via Electromagnetic Field Ratios

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Solution Overview

Problem

Existing electromagnetic transponder systems face challenges in authentication processes, which are energy and computationally intensive, sensitive to attacks, and reliant on cryptographic algorithms, making them inefficient and vulnerable.

Innovation Solution

A method using an electromagnetic transponder that authenticates a terminal by measuring and comparing current and voltage ratios across different resistive loads, allowing for a fast and energy-efficient authentication process independent of cryptography.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cryptographic algorithms are used for authentication between terminal and transponder, then security is improved, but energy consumption and computational intensity increase significantly

Engineering Contradiction:

Improveauthentication securityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces cryptographic algorithms (information processing system) with electromagnetic field measurements (physical field system). The authentication is based on measuring the ratio of electromagnetic field characteristics at different frequencies, substituting complex computational authentication with direct physical measurement, thereby reducing energy consumption and computational intensity while maintaining security.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the authentication parameter from cryptographic data exchange to electromagnetic field parameter ratios. By measuring the ratio of field strengths at different frequencies (f1 and f2), the system creates a unique physical signature for authentication, eliminating the need for energy-intensive cryptographic operations while ensuring secure identification.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If cryptographic algorithms are used for authentication, then security is improved, but processing time increases

Engineering Contradiction:

Improveauthentication securityVSAvoidauthentication time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces time-consuming cryptographic processing with immediate electromagnetic field measurements. The authentication occurs in real-time by continuously monitoring field ratios, eliminating the sequential processing delays inherent in cryptographic algorithms and enabling instant verification.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables continuous authentication by constantly measuring electromagnetic field ratios during normal operation. Unlike cryptographic methods that require discrete authentication exchanges, this system maintains continuous verification of the terminal's identity through ongoing field measurements, reducing total authentication time while maintaining security.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If cryptographic algorithms are used for authentication, then security is improved, but vulnerability to attacks increases

Engineering Contradiction:

Improveauthentication securityVSAvoidsusceptibility to attacks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the naturally varying electromagnetic field characteristics into a security feature. Instead of trying to eliminate field variations, the system uses them to create unique, unclonable authentication signatures. This approach transforms potential vulnerabilities (field variability) into security advantages, making the system resistant to attacks while eliminating the cryptographic vulnerabilities present in conventional systems.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 enables secure and efficient authentication of both the transponder and terminal, reducing energy consumption and computational intensity while enhancing security against unauthorized access.

Implementation Method 1

a terminal producing a magnetic field, by a transponder comprising an oscillating circuit from which a direct voltage is produced

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an oscillating circuit upstream of a rectifying circuit capable of supplying a DC voltage when the transponder is in the magnetic field of a terminal

Methodology Applied

Scientific EffectElectromagnetic energy conversion: Electromagnetic Induction

Data Source

PatentEP2267645B1Authentication of a terminal-electromagnetic transponder couple by the transponder

Publication Date: 2016.04.20 STMICROELECTRONICS (ROUSSET) SAS

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AI summary

The invention relates to a method of authenticating a terminal producing a magnetic field, by a transponder comprising an oscillating circuit from which a DC voltage is produced, in which the transponder: receives a first information ((I1empty/I1R20)MES) relating to the current (I1) in an oscillating circuit of the terminal, measured by the terminal for a first value (R20) of resistive load of the transponder; and exploits (55, 56) this first information and second information (VC2]R20, VC2]R21 relating to the level of said DC voltage, measured respectively for said first value of resistive load and for a second value (R21) of resistive load.