Authenticated Private Set Intersection: A Merkle Tree-Based Approach for Enhancing Data Integrity

2025-06-05

AI Summary

Existing private set intersection (PSI) protocols lack formal guarantees of data integrity, rendering them vulnerable to malicious parties that tamper with inputs or extract extraneous intersection information. This work introduces the first formal definition of data integrity in PSI and proposes the first authenticated PSI paradigm supporting integrity verification. Our approach deeply integrates Merkle trees with volePSI/mPSI protocols, augmented by zero-knowledge inclusion proofs, cryptographic hashing, and commitment schemes, yielding verifiable two-party and multi-party authenticated PSI protocols. The two-party protocol achieves communication complexity O(nλ + n log n), matching the optimal complexity of non-authenticated schemes; the multi-party variant attains O(nκ + n log n). A prototype implementation confirms the protocols’ security, correctness, and practicality.

Technology Category

• Machine Learning: Privacy
• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust
• Multiagent Systems: Mechanism Design

Application Category

• Security and Privacy: Data transparency and provenance
• Semantics and Knowledge: Provenance, trust, security and privacy, and ethical issues in managing semantic data
• Responsible Web: Data and user privacy-enhancing technologies for the Web

Abstract

Private Set Intersection (PSI) enables secure computation of set intersections while preserving participant privacy, standard PSI existing protocols remain vulnerable to data integrity attacks allowing malicious participants to extract additional intersection information or mislead other parties. In this paper, we propose the definition of data integrity in PSI and construct two authenticated PSI schemes by integrating Merkle Trees with state-of-the-art two-party volePSI and multi-party mPSI protocols. The resulting two-party authenticated PSI achieves communication complexity $mathcal{O}(n lambda+n log n)$, aligning with the best-known unauthenticated PSI schemes, while the multi-party construction is $mathcal{O}(n kappa+n log n)$ which introduces additional overhead due to Merkle tree inclusion proofs. Due to the incorporation of integrity verification, our authenticated schemes incur higher costs compared to state-of-the-art unauthenticated schemes. We also provide efficient implementations of our protocols and discuss potential improvements, including alternative authentication blocks.

Problem

• Enhancing data integrity in Private Set Intersection protocols
• Preventing malicious data extraction in PSI schemes
• Reducing communication overhead in authenticated PSI constructions

Innovation

• Integrates Merkle Trees with PSI protocols
• Ensures data integrity in set intersections
• Achieves efficient communication complexity