Reusable Fuzzy Vault Biometric Security
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Solution Overview
Problem
Existing fuzzy vault schemes are not secure against adversaries given multiple vaults locked under the same biometric information, and they lack reusable security, which is essential for protecting secret information using noisy biometric readings.
Innovation Solution
A reusable fuzzy vault (RFV) system is implemented, comprising a locking algorithm and an unlocking algorithm that utilize a fuzzy string generated from biometric readings to protect secret information, ensuring that no computationally bounded adversary can obtain the secret information even if multiple public strings are locked under the same biometrics. The system uses a public string vault and hash values to authenticate access, with the locking algorithm setting up a public vector, sampling a randomizer polynomial, and computing a polynomial to output a public string vault, and the unlocking algorithm decoding data points to retrieve the secret information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple vaults are locked under the same biometric information, then the system can protect multiple secret information, but the security is compromised against adversaries
Solution Approach 1:
The system segments the vault structure into multiple independent components, each associated with a specific secret information. Each vault contains a unique set of data points and polynomial that are mathematically independent from other vaults, even when locked under the same biometric information. This segmentation ensures that compromising one vault does not reveal information about other vaults or the underlying biometric secret.
Solution Approach 2:
The system introduces an intermediary polynomial construction mechanism that acts as a mediator between the biometric information and the multiple secret informations. The polynomial is constructed such that it embeds the biometric secret in a hidden manner while allowing multiple independent vaults to be generated. This intermediary structure prevents direct correlation between the biometric information and individual secrets, maintaining security across multiple vaults.
2Adaptability or versatility
If reusable fuzzy extractors are used to allow multiple enrollments, then the system can handle noisy biometric readings, but the security against adversaries is weakened
Solution Approach 1:
The system performs preliminary action by pre-constructing the polynomial structure during the first enrollment, embedding the biometric secret in a secure mathematical form. Subsequent enrollments with noisy biometric readings can be accommodated by the same polynomial structure through error-tolerant matching, without requiring re-construction that would expose the secret. This preliminary polynomial construction enables reusability while maintaining security.
Solution Approach 2:
The system allows parameter changes in the biometric input (noisy readings) while maintaining the same underlying polynomial structure and secret. The polynomial evaluation can tolerate variations in the biometric parameters within a certain threshold, enabling multiple enrollments with different noisy readings. The secret parameters remain unchanged and protected, while the system adapts to parameter variations in the biometric data.
3Productivity
If polynomial overhead is reduced to constant, then the system efficiency is improved, but the complexity of maintaining security increases
Solution Approach 1:
The system extracts the polynomial overhead from the per-vault operation and relocates it to a one-time setup phase. The polynomial structure is constructed once during initial enrollment with constant overhead, and subsequent vault operations simply evaluate this pre-constructed polynomial. This extraction of overhead to a preliminary phase improves efficiency while the security complexity is managed through the mathematical properties of the polynomial structure.
Solution Approach 2:
The polynomial structure serves multiple functions simultaneously: it protects multiple secret informations, tolerates noisy biometric readings, and enables multiple enrollments. This universal polynomial construction eliminates the need for separate complex security mechanisms for each vault or enrollment, reducing overall system complexity while maintaining constant overhead across all operations.
Data Source
AI summary
Described is a system for biometric based security. The system applies a reusable fuzzy vault (RFV) process to protect secret information. The RFV process comprises a locking algorithm and an unlocking algorithm. The locking algorithm takes as input a fuzzy string m generated from readings of biometrics and secret information sk to be protected, The locking algorithm outputs a public string vault and a hash value h of sk. The unlocking algorithm takes as input a public string vault and a fuzzy string m′, and outputs a string sk′ if fuzzy string m′ is sufficiently close to fuzzy string m. The unlocking algorithm further computes a hash value h′ of sk′ and compares it with h. The system allows access to the secret information sk when h′ is equivalent to h.