A Review on Blockchain-Based Trust & Reputation Schemes in Metaverse Environments

The metaverse represents a transformative integration of virtual and physical worlds, bring- 2 ing unprecedented opportunities for social interaction, commerce, education, healthcare, 3 and entertainment. Establishing trust in these expansive and decentralized environments 4 remains a critical challenge. Blockchain technology, with its decentralized, secure, and 5 immutable nature, is emerging as an essential pillar of trust and digital asset ownership 6 within the metaverse. This paper provides an extensive review of blockchain-enabled 7 trust and reputation frameworks specifically tailored to metaverse ecosystems. We present 8 an in-depth analysis of existing blockchain solutions across diverse metaverse domains, 9 including gaming, virtual real estate, healthcare, and education. Our core contributions 10 include a comprehensive taxonomy that classifies current trust and reputation schemes 11 by their underlying mechanisms, threat models addressed, and their architectural strate- 12 gies. We provide a comparative benchmark analysis evaluating key performance metrics 13 such as security robustness, scalability, user privacy, and cross-platform interoperability, 14 revealing critical trade-offs inherent in current designs. Our analysis finds that score-based 15 designs trade scalability for nuanced reputation representation, while SSI and SBT-based ap- 16 proaches improve Sybil-resistance but introduce significant privacy governance challenges. 17 Finally, we outline unresolved research challenges, including cross-platform reputation 18 portability, privacy-preserving computation, real-time trust management, and standardized 19 governance structures.