Research On Blockchain Rprivacy Protection And Its Supervision Mechanism

As a new disruptive technology,blockchain has revolutionised the operation mode of many traditional industries with its vision of decentralisation and social autonomy,and its characteristics such as high trustworthiness,immutability and traceability have indeed solved the historical ills of many industries.However,with the development of the "blockchain+" ecology,many problems have been exposed that need to be solved.For example,the open and verifiable nature of blockchain has led to the problem of privacy leakage;its decentralised and autonomous concept makes it difficult to reach the grip of state regulation,and complete freedom from certain regulation will inevitably lead to uncontrollable crimes.Therefore,in order to ensure the privacy and security of data on the chain,strengthen the regulatory grip and promote the construction of cybersecurity in the information age,the study of how to adopt secure and efficient technical means to provide blockchain data privacy services while incorporating regulatory mechanisms has become a hot research topic in academia nowadays.In addition,there are many problems with traditional digital asset trading solutions:(1)all data sold by users are transparent to trusted third parties,and the disclosure of certain sensitive data may lead to serious privacy leakage problems;(2)relying on third-party institutions for transactions will greatly weaken the security model of the system;(3)because the centralized data market is a centralized storage and management model,it is vulnerable to hacker attacks.Blockchain,as a new type of distributed storage database,has the characteristics of high trustworthiness,multi-point backup and traceability,etc.Using blockchain as the underlying support technology of the system can well solve the above problems.However,the existing related solutions generally have problems such as lack of regulation and transaction transparency.Therefore,it is still an open problem to study the blockchain digital asset trading scheme with privacy protection attributes,which is supervisable and fair.Specifically,the main work of this thesis is as follows.(1)To address the problem that privacy and regulation are difficult to coexist in the blockchain transaction process,a blockchain regulated privacy protection scheme(BPS)based on zero-knowledge proof is proposed,which achieves the hiding of account balance,transaction amount and transaction link relationship while allowing the process of transaction The BPS allows the monitoring of the transaction process.Specifically,the regulator organizes the identity of all legitimate users in the system into an identity authorization Merkle tree,and users only need to provide an identity authorization Merkle tree proof path to prove that their identity has been authorized during the transaction process,without revealing the identity authorization certificate,thus realizing anonymous authentication of user identity.At the same time,the zk SNARK technology constrains the user to generate the correct regulatory traceability data during the transaction,and afterwards,the regulator uses its own traceability key to revoke the anonymity of the transaction and trace the user’s identity.Further,the scheme utilizes tools such as cryptographic commitment mechanism,Merkle tree structure,pseudorandom function,and zk SNARK technique to achieve the concealment of transaction content and transaction link relationship.The security proofs show that the scheme satisfies the ledger non-disclosure,transaction unlinkability,and supervisibility.Finally,the performance of the scheme is verified using the libsnark library,and a comparative analysis is performed with other related schemes in terms of functionality and performance,and the strengths and weaknesses of the proposed scheme are comprehensively evaluated.(2)In response to the existing blockchain asset trading scheme,which has the problems of contract leakage of privacy,transparent transaction payment process,and lack of regulation,we propose a fair and regulable data asset trading scheme that provides complete protection of personal privacy.That is,our scheme not only achieves fairness and data privacy in transactions,but also avoids contractual leakage of privacy,while achieving privacy protection and transaction regulation of the payment process.Specifically,the data transaction process avoids contract leakage of privacy by using agent re-encryption technology,achieves data privacy and transaction fairness in an untrustworthy environment by using the Turingcomplete programming model of smart contracts and the knowledge leak-free nature of zeroknowledge proof,and at the same time,provides privacy protection and supervisory characteristics of the payment process by combining the advantages of the blockchain supervisable privacy protection scheme in Chapter 3.Subsequently,the expected security goals of the scheme: fairness,privacy,and regulability are demonstrated in detail from a theoretical perspective.Finally,the feasibility and correctness of the scheme are verified from an experimental perspective based on the Hyperledger Fabric blockchain platform,and a functional and performance comparison analysis is conducted with other related schemes to comprehensively evaluate the advantages and shortcomings of the proposed scheme.