Electronic Tag Authentication Using Dynamic Pseudo-Random Secrets

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Solution Overview

Problem

Electronic tags face security issues due to the risk of privacy exposure and traceability, particularly in retroactive scenarios, where attackers can intercept and decode secret information, compromising user privacy and requiring costly computational resources for security measures.

Innovation Solution

A method where the electronic tag uses a pseudo-random secret value that is updated regularly, combined with a pseudo-random generator to ensure secure communication, using a stream cipher approach that is computationally lightweight, allowing for efficient retroactive non-traceability without the need for extensive computational resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional secret-key authentication is used, then authentication functionality is provided, but retroactive traceability occurs allowing attackers to decode past communications

Engineering Contradiction:
Improveauthentication securityVSAvoidprivacy protection
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent applies dynamics by making the secret key dynamic rather than static. The secret key evolves over time through a chain of secret values where each value is derived from the previous one using a one-way function. This dynamic key evolution ensures that even if an attacker obtains a current secret value, they cannot retroactively compute previous values, thus preventing retroactive traceability while maintaining authentication security.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the secret key from a fixed value to a sequence of values that change over time. By using a one-way function to generate a chain of secret values (K0, K1, K2, ...) where each Ki is derived from Ki-1, the system transforms the static secret key parameter into a dynamic sequence, ensuring that past communications cannot be decoded even if current secrets are compromised.

Inventive Principle:
Principle #35Parameter changes

2Loss of information

If hash functions are used to ensure retroactive non-traceability, then privacy protection is improved, but computational complexity and manufacturing cost increase

Engineering Contradiction:
Improveprivacy protectionVSAvoidcomputational resources
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent employs cheap short-living objects by using simple one-way functions that can be implemented with minimal computational resources. Instead of complex hash functions requiring significant processing power, the invention uses lightweight one-way functions that generate secret value chains, making the system suitable for low-cost electronic tags with limited computational capabilities while still providing retroactive non-traceability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes complex cryptographic mechanisms with simpler mathematical functions. By replacing traditional hash-based approaches with a chain of secret values generated through simple one-way functions, the invention reduces computational complexity and manufacturing costs while maintaining the essential security property of retroactive non-traceability.

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

Data Source

PatentEP2193626B1Secure communication between an electronic label and a reader
Publication Date: 2018.12.26 ORANGE SA
  • EP2193626B1 patent drawingFigure 1~2
  • EP2193626B1 patent drawingFigure 3A~5
  • EP2193626B1 patent drawingFigure 3B

AI summary

The invention relates to a secure communication between an electronic label (A) and a reader (B), in particular for the authentication of the label by the reader, in which: the reader (31) transmits at least one datum (Ch) to the label, the label calculates a combination comprising at least the datum from the reader (Ch)) and a secret (Si) specific to the label, and the label communicates (32) the result (C(Si, Ch)) of the combination to the reader (B) for verification purposes. The aforementioned combination (C(Si, Ch)) is preferably calculated using a current secret value (Si) delivered by a pseudo-random number generator (33). The reader (B) is also provided with a homologous pseudo-random generator.