MetaL: A Fully Decentralized User-Driven Access Control Scheme for Metaverse Utilizing MC-ABE and Sharding Blockchain

In recent years, Metaverse has experienced rapid development and has shown significant potential in various fields. Secure access control protocols are crucial for protecting digital assets and virtual services within the Metaverse. However, existing research suffers from the issue of single points of failure, which threatens data security and privacy when facing malicious adversaries. Additionally, current solutions face scalability challenges, rendering them unsuitable for handling the massive volume of user requests in large-scale Metaverse environments. To overcome these limitations, this paper introduces Metaverse Lock (MetaL), a fully decentralized user-driven access control scheme designed for digital assets and virtual services in the Metaverse. MetaL leverages our designed multi-committee attribute-based encryption (MC-ABE) scheme with a partially synchronous communication model, which enhances the security and fault-tolerance of attribute-based encryption. Additionally, MetaL integrates sharding blockchain technology and consensus algorithms to ensure consistency and liveness within the committee and provide immutability of the key information. The expansion of the committee enhances security and fault tolerance but also introduces additional efficiency overhead. To address this, we propose an innovative double-layer sharding architecture. Experimentally, we present a proof-of-concept implementation of both MC-ABE and MetaL, demonstrating that our approach significantly improves fault tolerance while maintaining an acceptable overhead.