Homomorphic Encryption for Secure Biometric Collation

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Solution Overview

Problem

Existing biometric authentication systems face challenges in protecting biometric information, particularly when repeated authentication occurs, and in ensuring that authentication data remains secret from servers and server managers, with existing solutions like dual homomorphism encryption being computationally costly and difficult to implement in real-time.

Innovation Solution

A collation system comprising nodes that encrypt authentication data with a public key, calculate distances between authentication target data and authentication data in an encrypted state, and generate collation data using a polynomial with a threshold value, allowing for secure comparison without decrypting the data, utilizing additive homomorphism encryption to maintain data secrecy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If biometric authentication is performed repeatedly using the same template, then authentication functionality is maintained, but biometric information protection strength deteriorates

Engineering Contradiction:

Improveauthentication functionalityVSAvoidbiometric information protection strength

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary encryption of biometric templates using homomorphic encryption before storage. This preliminary action ensures that even when templates are stored and reused multiple times, they remain protected in encrypted form, preventing the deterioration of protection strength while maintaining authentication functionality across repeated uses

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces encrypted template data as an intermediary between the original biometric information and the authentication process. This intermediary encrypted form allows authentication operations to be performed without exposing the actual biometric data, thereby maintaining both authentication functionality and protection strength over repeated authentications

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If authentication data is stored in plaintext on the server, then collation processing is simple and fast, but data leakage risk increases

Engineering Contradiction:

Improvecollation processing speedVSAvoiddata leakage risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical approach of storing and processing plaintext data with a cryptographic system based on homomorphic encryption. This substitution allows the server to store and process encrypted data directly, eliminating data leakage risks while maintaining collation functionality through cryptographic operations that preserve computational efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Encrypted authentication data serves as an intermediary that enables the server to perform collation operations without accessing the actual plaintext information. This intermediary encrypted form protects against data leakage while allowing the server to efficiently process authentication requests through homomorphic decryption of comparison results

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If biometric templates are encrypted using conventional encryption, then data secrecy is improved, but authentication collation becomes impossible without decryption

Engineering Contradiction:

Improvedata secrecyVSAvoidauthentication collation complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the cryptographic parameter from conventional encryption to homomorphic encryption, which possesses the special property of allowing mathematical operations on encrypted data. This parameter change enables authentication collation to be performed directly on encrypted templates without full decryption, maintaining data secrecy while reducing collation complexity to simple cryptographic operations

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Homomorphic encryption acts as an advanced intermediary that bridges the gap between data secrecy and collation capability. Unlike conventional encryption that completely blocks processing, this intermediary encrypted form allows the server to perform necessary authentication operations while maintaining secrecy, reducing the complexity of the overall authentication system

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9910478B2Collation system, node, collation method, and computer readable medium

Publication Date: 2018.03.06 NEC CORP

AI summary

A collation system includes a first node, a second node and a third node. The first node includes: an encryption unit; a distance calculation unit t; and a collation data generation unit. The second node includes: a key generation unit; and a collation unit. The third node includes: a storage unit; and a collation information generation unit.