Biometric Input Encryption Using Split Parameters for Secure Collation
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Solution Overview
Problem
Biometric authentication systems face challenges in maintaining collation accuracy while reducing the risk of information leakage, as existing cancelable biometrics use the same secret key for registration and collation, leading to potential security vulnerabilities.
Innovation Solution
Implement a terminal apparatus and collation system that utilize multiple parameters for encrypting and transforming input information, including a terminal-side storage area, acquisition units, and transformation parameter generation units to generate encrypted input information, reducing the risk of information leakage and maintaining collation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same secret key is used for both registration and collation in cancelable biometrics, then the system is simpler to implement, but the security risk increases due to potential information leakage
Solution Approach 1:
The secret key is segmented into two distinct parts: a first key used for registration and a second key used for collation. This segmentation allows the system to maintain simplicity while improving security, as each key serves a specific function and the compromise of one key does not affect the other. The patent implements this by dividing the encryption key into multiple components that are used at different stages of the biometric authentication process.
Solution Approach 2:
A key management server is introduced as an intermediary to securely manage and distribute the first and second keys to terminal devices. This intermediary approach allows the system to use multiple keys without significantly increasing complexity at the terminal level, as the key management burden is shifted to the server. The server acts as a mediator that coordinates key usage across the system while maintaining security.
2Reliability
If different parameters are used for encryption and transformation, then information leakage is reduced, but the system complexity increases
Solution Approach 1:
The system changes the encryption parameters between registration and collation stages by using different keys (first key for registration, second key for collation) and different transformation approaches. This parameter change ensures that even if one stage is compromised, the other remains secure. The patent implements this by applying distinct cryptographic parameters at each stage of the biometric processing pipeline.
3Reliability
If biometric information is compromised, then the authentication system security is impaired, but the biometric information cannot be discarded or updated like IC cards
Solution Approach 1:
The system performs preliminary encryption of biometric information using the first key during registration, creating an encrypted version that can be safely stored. This preliminary action ensures that the original biometric information is never stored in plaintext, and if compromised, the system can regenerate encryption keys without needing to update the actual biometric data. The patent implements this by encrypting biometric features before storage and using key regeneration for cancellation purposes.
Solution Approach 2:
The system changes the encryption parameters (keys) rather than the biometric information itself when cancellation is needed. By regenerating the first or second keys, the system effectively invalidates previous encrypted data without needing to update or re-collect biometric information. This approach provides adaptability similar to discarding IC cards while maintaining the immutability of actual biometric data.
Data Source
AI summary
In order to realize encryption processing capable of suppressing the degradation of collation accuracy and reducing the risk of information leakage, a terminal apparatus for encrypting input information to be input for collation is provided, the terminal apparatus being configured to perform transformation parameter generation processing for generating a transformation parameter based on a first parameter stored in a storage area and a second parameter that is different from the first parameter, and encrypt the input information input for collation using the transformation parameter to generate encrypted input information.