A Verifiable and Redactable Blockchain with Lightweight Storage and Permission Supervision

As a promising decentralized paradigm, the verifiable and redactable blockchain offers a feasible solution for achieving authorized and controlled redaction of on-chain data. However, existing schemes suffer from rapidly expanding ledgers caused by authentication data structures and fail to strike a balance between permission supervision and redaction efficiency. In this paper, we propose a novel verifiable and redactable blockchain scheme that introduces a dual-level authentication architecture to achieve lightweight storage and permission supervision. To this end, we first design a dual-level authentication data structure that appends all blocks to a constant-size global tag, while supporting verifiable redaction and query over on-chain data. Likewise, we introduce a dual-level chameleon hash structure, which not only employs committee members holding sub-keys to redact on-chain data but also enables the certificate authority to use the master key to correct malicious redactions executed by corrupted committee members. Furthermore, we propose an efficient auditing protocol to enhance the integrity and consistency of the blockchain ledger during the process of synchronous circulation. Finally, both security analysis and performance evaluation prove that the proposed scheme is practical.