Blockchain-Based Privacy-Preserving Reputation Systems

Abstract

Privacy-preserving reputation systems are critical for decentralized Web3 environments, where trust must be managed without centralized authorities. This paper presents a blockchain-based protocol leveraging Subjective Logic (SL) and Hybrid Homomorphic Encryption (HHE) to securely aggregate reputation scores while preserving user privacy. Subjective Logic enables modeling trust with quantified u ncertainty, a llowing for m ore fl exible tr ust enforcement across decentralized identity systems, marketplaces, and DAOs. To enhance performance and confidentiality, we integrate the PASTA symmetric cipher for efficient encryption of auxiliary data. Our protocol enables encrypted reputation aggregation, smart contract-based trust enforcement, and selective disclosure via zero-knowledge proofs. The proposed design balances efficiency, scalability, and privacy, making it well-suited for dynamic Web3 ecosystems requiring decentralized, privacy-preserving trust mechanisms.