Design And Implementation Of A Trusted Data Sharing System Based On Asymmetric Encryption Algorithm

With the increasing value and the growing scale of data,it is becoming more and more important to use data sharing mechanism to extract potential value behind data.In today's social environment,how to allow data owners to get rid of suspicion,trust each other to avoid illegal access or attack to data,which are the basic requirements and consensus of data sharing.The problem of distrust can be solved in traditional data sharing system which relies on centralized sharing scheme,but data are concentrated on the third party mechanism.Once attacked,there is a risk that the data may be deleted or modified.Blockchain uses basic techniques such as asymmetric cryptography(hash algorithm and digital signature algorithm)to make it have the characteristics of de-trust and decentralization,which can change the traditional centralization mechanism.The nodes in the blockchain system exist equally.Maintaining a reliable database collectively can solve the problem of malicious attack effectively.Data deletion or modification becomes almost impossible,which increases the credibility and security of data.In view of this,a trusted data sharing system based on asymmetric encryption algorithm is put forward in this paper.Asymmetric encryption technology is used to process user-shared data.The hash algorithm is used to extract the file data digest.The digest is signed and verified by digital signature algorithm.The P2P network is used to transmit and receive encrypted data.Finally,record-files are used to record the basic information of users' uploading files.Asymmetric encryption technology and the indiscriminate modification of record-files improves the credibility and data security of the system.The main research work and results are showed as follows:1.The system is divided into user register and login module,data upload and download module,and record-files management module.The three major modules are further divided into eight sub-modules.The requirements analysis and detail design of each module are given.The record-files management module updates record-files,and records the whole network data at the same time,the whole network record-files can be regularly exchanged and tested.This module also provides historical records query operation for the users;Hash algorithm(MD5)and digital signature algorithm(MD5withRSA)in the asymmetric encryption and P2P network(multicast communication mode)are used in data upload module and verification module.Link characteristics and Merkle Tree technology are used in record-files update and detection modules.2.The system is implemented by JavaWeb programming technology,further developed and tested in the Eclipse integrated environment,it can realize the system development and share the data smoothly.The main test results of sub modules are as follows:(1)In the data upload module,the MD5 algorithm can successfully calculate the MD5 value of each file,the system generates a private key and signs file message by the MD5withRSA digital signature algorithm,and the multicast mode object transfers the signature data to the network.(2)The data validation module can successfully receive the data in the network and verify the processing.(3)The record-files update can record the whole network success upload information according to the set content format,and the new block file can be automatically generated at every hour.(4)In record-files detection module,the system detects whether the local record-files are the same as the whole network data every 5 minutes.If there is any modification,the data is repaired immediately,so as to ensure the consistency of the record-files3.Joint test between modules.Test the operation consistency.After successful login,different users can simultaneously upload and share files,and they also can consistently record the basic information of all uploaded files to the latest record-file according to the successful upload time.At the same time,users can also query the history of uploading records and download files.Test the consistency and tampering of the record-files.All record-files obtained by different users are completely consistent,and all successful upload records before the current time are completely recorded.If a record-file is maliciously deleted or modified,the timing detection module will restore the data,the next obtained record-files are still complete files that have not been modified.The test shows that:the full history of the record file can ensure the integrity of the data,Anti-tamper characteristics strengthen the security of shared data protection.The system provides users with a secure and trusted data sharing platform.