Research And Design Of Privacy Protection Scheme For Account-based Blockchain System Like Ethereum

With the release of cryptocurrency Libra,countries around the world have invested in the research of its underlying blockchain technology.Blockchain has also been gradually applied to various fields such as finance,Internet of Things,and the Internet Industry.As the blockchain 2.0 platform,Ethereum's turing complete programming language and smart contract components make the platform widely used in many blockchain projects.However,with the further advancement of the commercialization of blockchain technology,the privacy and security issues of it have gradually become more prominent.The transparent data storage model and the open transaction process throughout the network make the blockchain system suffer from serious privacy leakage problems.Research on this issue has become an important subject in the field of blockchain.Aiming at the privacy issues of the blockchain,this article focuses on the privacy protection schemes for account-based blockchain systems such as Ethereum.By improving and combining the existing privacy protection technology,this paper proposes a privacy protection mechanism RZcash applicable to the Ethereum system.The main innovations of this article are summarized as follows:(1)Aiming at the problem of redundancy of key-pairs in the design of Ethereum privacy protection,this paper proposes the ciphertext equivalent signature scheme(CEs)based on the ciphertext equivalence test commitment scheme.Based on the original private key of the account,this scheme generates a new public key by constructing a ciphertext equivalent commitment.The design of this solution makes it unnecessary for users to regenerate a new pair of public and private keys when using the privacy protection service,thereby avoiding increasing the key management cost of the blockchain system and reducing the risk of key leakage at each node.(2)By summarizing and improving the existing cryptographic technologies,this paper proposes a privacy protection mechanism RZcash designed for blockchain systems such as Ethereum.This mechanism implements verifiable dynamic hiding of account balances and transaction amounts through the range proof scheme,the zero-knowledge proof scheme,etc.At the same time,this article also proposes the transaction construction and interaction mechanism between different types of accounts in RZcash,and shows how RZcash can be better embedded in the existing blockchain system to provide privacy protection services.