Research And Implementation Of Privacy Protection Technology In Blockchain

With a new round of technological revolution and industrial change sweeping the world,the emergence of new technologies such as cloud computing,big data,blockchain and so on has profoundly changed the production and life style of modern people,which has become a new driving force of economic growth.Blockchain records data information in a distributed way,and all participants record it together.These information will be stored in all nodes,rather than just a unique centralized mechanism like the traditional database.Therefore,in terms of security,it achieves a qualitative breakthrough compared with the traditional technology.However,due to the differences between traditional technologies and blockchain technology,many common privacy protection schemes are not applicable in blockchain applications.Therefore,it has become an important research direction to analyze the privacy security in blockchain,to study targeted privacy protection schemes and to improve the anonymity of blockchain.The main work of this paper is to improve the anonymity of blockchain by using secure signature algorithm and mixed currency technology to break the direct link between transactions.It can be divided into the following parts:(1)In this paper,a new blind signature algorithm based on SM2 algorithm is proposed.By introducing two random blinding factors in the blinding stage,the blinding is realized,which ensures the privacy protection of signature information.At the same time,the algorithm satisfies the validity,untraceability and non-repudiation of the blind signature algorithm,and the existence of adaptive chosen-message attack can not be forged.(2)A privacy protection scheme based on mixed currency technology is designed in combination with blind signature algorithm.This scheme breaks the direct link between transactions,and uses the characteristics of blind signature to hide signature messages to realize the anonymity of the mixed currency process information to the mixing center.Finally,it is proved that the scheme can not be forged,linked and traced,and a variety of attacks are analyzed.(3)A privacy protection system based on blockchain is designed and implemented.Through the experiment and analysis of the proposed blind signature algorithm based on SM2 and privacy protection scheme based on mixed currency technology,it shows that the scheme has higher efficiency and anonymity.In this paper,java development language is used to design and implement the privacy protection system,which is mainly managed by users and mixed currency protocol.Based on these two functional modules,the user client and the mixing center server are designed to complete the transaction without disclosing the specific transactions of users to the mixing center.Through the system experiment,this schema realizes to improve the anonymity of user identity by breaking the link between transactions.