Message Control for Blockchain Rewriting

Blockchain rewriting is necessary for modifying illegal or invalid messages included in blockchain transactions, while maintaining the consistency of subsequent blocks in the blockchain. However, arbitrary blockchain rewriting is not desirable as it defeats the purpose of blockchain rewriting. In this work, we propose a new security primitive named message-controlled chameleon hash (MCH) and apply it for message control in blockchain rewriting to ensure that no unspecified messages are generated from blockchain rewriting. The proposed MCH enables permitted parties to select candidate messages from designated message sets for blockchain rewriting at the message level. Our evaluation shows that the performance of MCH is comparable to the classic CH [26] and the state-of-the-art CH [16]. We also show that the proposed MCH can be easily integrated into both permissioned and permissionless blockchains.