Supplementary Token Signatures for Quantum-Resistant ID Data

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Solution Overview

Problem

Existing cryptographic methods used in ID tokens, such as passports and identity cards, are vulnerable to decryption by quantum computers due to their reliance on RSA or ECC, posing a risk to the security and authenticity of stored data over long validity periods.

Innovation Solution

A supplementary cryptographic signature is added to the ID token using a post-quantum key, such as a PQC key, which is created by a signature device and stored on the token, enhancing tamper-proof security by requiring a different attack method than existing mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing cryptographic methods (RSA or ECC) are used for securing ID tokens, then current security standards are met, but vulnerability to quantum computer attacks increases

Engineering Contradiction:
Improvesecurity against quantum attacksVSAvoidvulnerability to quantum decryption
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the cryptographic security into two independent layers: the original ECC-based signature mechanism and a new supplementary quantum-resistant signature mechanism. Each layer operates independently with its own key pairs and verification processes, allowing the system to maintain backward compatibility while adding quantum security without compromising the existing infrastructure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the cryptographic parameter regime by introducing post-quantum cryptographic algorithms that rely on different mathematical assumptions than traditional ECC. The supplementary signature uses cryptographic parameters that are secure against quantum attacks, fundamentally changing the security landscape from quantum-vulnerable to quantum-resistant

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a supplementary cryptographic signature is added to the token, then quantum security is enhanced, but storage space requirements increase

Engineering Contradiction:
Improvetamper-proof securityVSAvoidstorage space on token
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies partial action by selecting only the essential components needed for quantum security - specifically, a hash value of the data structure and a supplementary signature. This partial approach provides sufficient quantum protection without requiring complete cryptographic replacement, thereby minimizing storage overhead while achieving the security goal

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If a supplementary cryptographic signature is added to the token, then quantum security is enhanced, but device complexity increases

Engineering Contradiction:
Improvedata integrity verificationVSAvoidsignature verification process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements universality by designing a verification system that can handle both the original ECC signature and the new quantum-resistant signature using a unified approach. The verification device can process both signature types through consistent procedures, and the supplementary signature can be verified independently or in conjunction with the original signature, providing flexible multi-functional security verification

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4704375A1Securing data stored in a token by supplementing a signature
Publication Date: 2026.03.04 BUNDESDRUCKEREI GMBH
  • EP4704375A1 patent drawingFigure 1A~1B
  • EP4704375A1 patent drawingFigure 2A~2B
  • EP4704375A1 patent drawingFigure 3

AI summary

The invention relates to a method and electronic system for supplementing and verifying a supplementary cryptographic signature in a digital token. For this purpose, after mutual authentication of the digital token and a terminal, a supplementary cryptographic signature is created by a signature device based on a secret key not previously used for this digital token and stored in the digital token. The supplementary signature can then be verified using an associated public key.