Design And Implementation Of A Private Data Cloud Storage And Sharing Scheme Based On Blockchain

Traditional cloud storage designs usually store files uploaded by users in plain text and share them with others through extraction codes and public download links.At the same time,the central server centrally manages file metadata such as file identifier and index information,and provides file routing services.This design mode has the following problems,the first is that the stored files may be accessed or copied maliciously;the second is that once the download address and extraction code of the file flow out,the file data is easy to be seriously leaked;and the third is that the file metadata stored in the central server is easily damaged or tampered with due to a single point of failure or malicious intrusion,These problems not only seriously threaten the user's data privacy and file ownership,but also may cause the files stored in the system can not be accessed normally.In order to solve the above three shortcomings of traditional cloud storage,this thesis proposes a private data cloud storage and sharing scheme based on blockchain.In this scheme:To protect the privacy of file data,this scheme designs a data encryption mechanism based on symmetric encryption algorithm and asymmetric encryption algorithm,and stores users' files and file keys in the cloud after encryption,which avoids data content from being maliciously peeked at by others,and ensures the privacy and security of data.In view of the risks of file sharing,a file sharing method based on proxy re-encryption is designed,which can effectively avoid the problem that data may be leaked in the sharing process,and ensure that the data sharing process in the cloud environment is secure and reliable.Aiming at the problem of metadata loss and malicious tampering in cloud storage,this scheme use the immutable and decentralized characteristics of blockchain to design a blockchain based data storage model and data recovery mechanism,which realizes the reliable storage of critical data such as file metadata and sharing information,and ensures that the data can be effectively recovered after damage or tampering,which improves the protection strength of user file data.Finally,this thesis verifies the system implemented from the scheme through experiments,and at the same time,experimentally determines the file fragment size used by the distributed file storage module,and analysis how the blockchain influence the system performance Based on the experimental data.The experimental results show:The running status and process design of the components in the system are correct,the files and file keys are effectively encrypted in the cloud,and there is no risk of leakage in the data sharing process.In addition,while the blockchain data storage strengthens the file data protection,the access performance of the data on the chain can also meet the application requirements.