Design And Implementation Ofaredactable Blockchain Scheme Based On Id-based Chameleon Hash

With the rapid development of digital currency and cryptography,blockchain technology has attracted attention from all walks of life.Blockchain technology guarantees the security of data due to its unique immutability.However,the immutability of blockchain is also accompanied by some disadvantages.If illegal informations are stored in the blockchain system,they cannot be cleaned up,which is in conflict with some laws and regulations.In addition,some of the user’s error information stored in the blockchain by mistake can not be redacted too.Therefore,it is very important to study the redactable blockchain scheme to solve the above problem.To meet the need for regulators and users to modify historical transactions on the blockchain,in this paper,an redactable block chain scheme based on identity-based chameleon hashing with high security and practicability is designed.The main research contents and innovations of this paper are as follows:(1)To solve the problem of key exposure free in chameleon hash,we propose an identity-based chameleon hash algorithm based on double random random values.This algorithm solves the problem of key exposure free and realizes the characteristics of identity based cryptosystem.Experimental results show that the proposed algorithm has good avalanche effect and diffusion effect,and the key generation,hash calculation and hash collision calculation of this algorithm have good running efficiency.(2)To solve the problem of difficult supervision of blockchain data,We propose an redactable blockcha in scheme using identity-based chameleon hash.In this scheme,an identity-based Merkle tree construction method and a new transaction signature method which can still be verified after the transaction is redacted are designed to achieve editable characteristics through the proposed identity-based chameleon hash.The final redactable blockchain allows users to modify additional data in old transactions using their key of identity,and regulators to modify additional data in any transaction using the master key of the system.Experimental results show that the performance of the main components of the proposed scheme can support the operation of typical blockchain application scenarios.