Abstract: The blockchain has the characteristics of decentralization, traceability, and immutability. However, its immutability makes some illegal information on the chain permanently retained. To solve this problem, a redactable blockchain scheme based on committee mechanism is proposed. First, the committee members are selected by applying the random sortition algorithm. Then, a decentralized editing strategy of voting consensus with the consensus mechanism is adopted based on proof of stake for users’ editing requests. In addition, the chameleon hash function is used to modify the data on the chain and an accountability mechanism is introduced to prevent users from malicious actions. Finally, the security and convergence of the scheme are demonstrated theoretically, and simulation results verify that the proposed scheme can efficiently modify the block content in a decentralized environment without affecting the consistency of the blockchain.

Key words: blockchain, redactable, committee mechanism, cryptographic sortition