Abstract:

The chameleon hash algorithm that can realize data editing provides a content controllable method for blockchain.However,once a participant obtains permission to edit the data,he can rewrite anything without being punished for his malicious behavior.At present,most redactable blockchain schemes can only punish malicious users without considering the malicious tampering of the blockchain by editors,which cannot realize the fairness of both users and editors at the same time.A fair and redactable blockchain scheme that supports malicious punishment is proposed,which ensures the fairness of the redactable blockchain scheme by effectively restricting the rights of editors and punishing their malicious behaviors.In the proposed scheme,the chameleon hash with a short-term trapdoor is used,so that editors and users must cooperate to complete the editing of the blockchain,which effectively restricts the rights of editors.Based on the secret sharing and signature schemes,a punishment mechanism for malicious editors is proposed to punish the malicious tampering behavior of editors and resist the malicious reports of users.Theoretical and experimental analysis shows that the proposed scheme not only realizes the collision-resistance and semantic security of blockchain data,as well as the fairness of users and editors in the data editing process,but also has a lower computational cost than existing schemes.In addition,the advantages of the proposed scheme become more obvious with the increase in the number of editing times,so it is of more practical application value.

Key words: redactable blockchain, chameleon hash, ephemeral trapdoor, secret sharing