Privacy-Preserving Credential Verification Using Garbled Circuits
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Solution Overview
Problem
Standardized digital signature schemes, such as RSA, DSA, and EC-DSA, require users to reveal private information to verify possession of credentials, compromising privacy, and non-standardized schemes necessitate system redesigns, which are not commonly employed.
Innovation Solution
The use of garbled circuits, message authentication codes (MACs), and proof of knowledge protocols, like sigma and schnorr protocols, allows users to prove possession of valid credentials without revealing them, employing commitment functions and MACs to verify hash values and messages using existing standardized signature schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standardized signature schemes (RSA, DSA, EC-DSA) are used to prove credential possession, then verification efficiency is maintained, but private information must be revealed compromising user privacy
Solution Approach 1:
The patent introduces garbled circuits as an intermediary mechanism between the prover and verifier. The garbled circuit allows the verifier to check credential validity without directly accessing the underlying private information. The circuit computes verification logic on encrypted inputs, acting as a mediator that preserves privacy while maintaining verification reliability.
Solution Approach 2:
The verification process is segmented into multiple components: commitment functions, garbled circuit construction, MAC verification, and proof of knowledge protocols. Each component handles a specific aspect of verification, allowing the system to maintain efficiency while protecting different layers of information separately.
2Loss of information
If non-standardized signature schemes are used to protect privacy, then user privacy is preserved, but system redesign is required increasing complexity
Solution Approach 1:
The patent makes garbled circuits universal by designing them to work with standardized signature schemes rather than requiring custom non-standardized schemes. The garbled circuit framework can verify multiple types of credentials (RSA, DSA, EC-DSA) using the same underlying technology, eliminating the need for system redesign while preserving privacy.
Solution Approach 2:
The patent changes the parameters of existing standardized schemes by adding layering techniques, commitment functions, and MACs to the traditional signature verification process. This allows the use of well-established schemes with modified parameters that provide privacy protection without requiring complete system redesign.
3Loss of information
If garbled circuits are used to prove credential possession without revelation, then privacy is enhanced, but computational overhead increases
Solution Approach 1:
The patent applies preliminary action by pre-computing and caching garbled circuits for common verification operations. The circuits are constructed in advance and can be reused multiple times, significantly reducing the computational overhead during actual verification processes. Commitment functions are also established beforehand to streamline the verification flow.
Solution Approach 2:
The patent uses copying by creating multiple representations of the same credential information in different forms (original credential, commitment, garbled circuit input). These copies serve different purposes: the original for the prover's records, the commitment for verification, and the garbled circuit input for privacy-preserving validation, distributing the computational load across different data representations.
Data Source
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AI summary
Standardized digital signature schemes (e.g., Rivest-Shamir-Adleman (RSA), Digital Signature Algorithm (DSA), Elliptical Curve Digital Signature Algorithm (EC-DSA), etc.) may be employed to prove authenticity of a message containing credentials. Proving possession of valid credentials may be performed using a combination of garbled circuits with message authentication codes (MACs) and proof of knowledge protocols (e.g., Sigma protocol, Schnorr protocol, etc.). Such techniques may allow proving entities to prove possession of valid credentials using standardized signature schemes without revealing those credentials directly to a verifying entity.