Biometric Cryptosystem Using Neural Network Vector Mapping

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Solution Overview

Problem

Current biometric template protection schemes face challenges in achieving irreversibility, unlinkability, and renewability while maintaining recognition performance, particularly due to vulnerabilities in feature transformation and biometric cryptosystem schemes that are susceptible to security threats and cross-comparison attacks.

Innovation Solution

A biometric cryptosystem that employs random projection and artificial neural networks to map biometric vectors to secret vectors, ensuring irreversibility and unlinkability by projecting biometric feature vectors onto random subspaces and using error correction coding, thereby enhancing security and recognition accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If feature transformation schemes (e.g., Biohashing, Bloom filter-based schemes) are used to protect biometric templates, then template security is improved, but the schemes are vulnerable to stolen-token scenario attacks and cross-comparison attacks

Engineering Contradiction:
Improvetemplate securityVSAvoidvulnerability to stolen-token and cross-comparison attacks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary transformation process using orthogonal matrices and non-linear functions between the original biometric template and the protected template. This intermediary layer (comprising orthogonal transformation followed by non-linear mapping) prevents direct access to the original biometric data, thereby defending against stolen-token attacks while maintaining template security

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transforms the biometric template by changing its parameters through orthogonal transformations and non-linear functions. The protected template is generated by applying these parameter transformations, which preserve the essential biometric information for recognition while altering the template structure to prevent cross-comparison attacks and enhance security

Inventive Principle:
Principle #35Parameter changes

2Reliability

If other cancellable biometrics (CB) schemes are used to overcome stolen-token scenario vulnerabilities, then security against stolen-token attacks is improved, but the protected templates are exposed to cross-comparison attacks and biometric recognition performance is seriously degraded

Engineering Contradiction:
Improvesecurity against stolen-token attacksVSAvoidcross-comparison attacks and recognition performance degradation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies orthogonal transformations and non-linear functions to transform the biometric template parameters, creating a protected template that maintains recognition performance. The orthogonal transformation preserves the Euclidean distance structure, while the non-linear function adds complexity to prevent cross-comparison attacks without significantly degrading recognition accuracy

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If biometric cryptosystems with error correction coding are used to handle intra-user variation, then tolerance to template-probe differences is improved, but it is difficult to achieve unlinkability because any linear combination of error correction codewords may also be a codeword

Engineering Contradiction:
Improvetolerance to template-probe differencesVSAvoidunlinkability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an intermediary orthogonal transformation layer between the biometric template and the error correction coding process. This intermediary transformation ensures that even with linear combinations of codewords, the original biometric information cannot be recovered, thereby achieving unlinkability while maintaining tolerance to intra-user variations through the error correction capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3669297B1A biometric cryptosystem
Publication Date: 2024.07.03 NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY (NTNU)
  • EP3669297B1 patent drawingFigure 1
  • EP3669297B1 patent drawingFigure 1
  • EP3669297B1 patent drawingFigure 2

AI summary

According to an aspect of the invention there is provided a method of enrolling a biometric sample in a cryptosystem scheme. The method comprises extracting biometric feature data from a biometric sample; generating a biometric vector from the biometric feature data; generating secret data; generating a secret vector from the secret data; combining the biometric vector and the secret vector using an artificial neural network, the artificial neural network configured to output a neural network model; and, storing the neural network model in a database, thereby enrolling the biometric sample in a cryptosystem scheme and facilitating subsequent verification through authenticating released secret data, released from the neural network model, whilst hiding the biometric feature data and the secret data. A method of verifying a biometric sample is also provided. Computer readable medium and systems are also provided.