MDID: A Multi-layer Blockchain-based Secure and Scalable Decentralized Identity Scheme for Web 3.0

The rapid evolution of Web 3.0 demands decentralized identity management systems that are secure and scalable. Existing Decentralized Identity (DID) solutions struggle with single points of failure (SPOF), forgeability, and limited scalability challenges, restricting their applicability in large-scale ecosystems. To address these challenges, we propose MDID, a multi-layer blockchain-based DID framework optimized for Web 3.0. MDID features a four-layer architecture that enhances interoperability and scalability across diverse DID systems. Security is reinforced through the Redundant Byzantine Fault Tolerance (RBFT) consensus protocol and the threshold signature algorithm, ensuring robust decentralization, SPOF mitigation, and unforgeability. The introduction of the Sharded Merkle Patricia Tree (SMPT) further optimizes DID management by enabling rapid and efficient storage and retrieval of (DID, Metadata) key-value pairs. Experimental results demonstrate MDID’s superior performance, achieving cross-domain credential verification in under 2 seconds, maintaining high operational efficiency in large-scale environments, and offering strong resistance to identity forgery and system disruptions. This work lays a critical foundation for advancing secure, scalable, and efficient decentralized identity management in Web 3.0 ecosystems.