Research On Privacy Protection Mechanism Based On Blockchain

With the rapid development of modern information technology and network,the level of digitization and informatization is higher and higher.The information society provides convenience for human beings in more aspects,at the same time,the problem of data privacy also produces a very big effect to the life and work.In health care,financial services,education,data privacy protection has become a top priority,especially in the field of medical treatment,medical data leakage may even lead to the patient's health information illegally selling fall into the hands of criminals,therefore,under the background of the big data,the privacy and controllability of data information has become the focus of attention.The storage,sharing and calculation of medical data all can reflect the privacy and security,existing models have many shortcomings,on the one hand,there are strict restrictions on data in sharing,calculation and other aspects,so they take a lot of time and resources,on the other hand,most of the existing computing models rely on the third-party institutions,the unreliability and the controllability to the information of the third party lead to the information security cannot be guaranteed,which is easily to appear a large number of privacy problems.Considering the characteristics of blockchain are decentralized and untamable,this paper uses blockchain to improve the problem of privacy protection in storage,sharing and other aspects,at the same time to save unnecessary time and resources.The research work of this paper is as follows:First,a blockchain-based storage scheme is proposed.Owing to the data is stored on the blockchain,so a large amount of data will be synchronized in the block along with block synchronization,which takes up space and leads to resource waste.For the problem of wasting storage space,we first propose a extensive storage model,in this model the information is stored in the node with high reliability,which saves the resources occupied on the blockchain.Then comparing the storage space with the extensive storage model,a method combining on-chain storing and off-chain storing is proposed,in this model the index information is stored on the chain,and the large-scale privacy data information is stored hierarchically off the chain.Through comparing several storage methods,the simulation result shows that the improved storage method can further improve the storage efficiency and save the storage space.Secondly,a blockchain-based sharing scheme combining attribute encryption using access-control with the agent re-encryption is proposed,so that the shared users can be changed from single to a group meets the access requirements.The performance and the security of this scheme are analyzed,then the experiment is carried out and the efficiency is analyzed by simulation.The simulation result shows that the sharing scheme based on blockchain is more secure and efficient than the existing scheme,which improves sharing efficiency under the premise of protecting data privacy.Lastly,an effective privacy data processing scheme based on blockchain is proposed.We studied consensus algorithm and encryption algorithm of the blockchian.An improved PBFT consensus algorithm to ensure the consistency between nodes is proposed,then based on the Map Reduce parallel computing framework,an improved homo morphic encryption algorithm is put forward for data processing and secure computing in cipher without decrypting the privacy data by increasing the number of bits in the encrypt plaintext and shortening the public key size.Finally,the correctness and security of the scheme are analyzed,and a comparative analysis is conducted between the scheme and the traditional privacy data processing scheme through experiments.The analysis results and simulation results show that the scheme has the advantages of high performance when there is a large amount of data,and greatly improves the operation efficiency.