The Design And Implementation Of Sharing Data Securely Based On Blockchain

With the rapid development of computers and networks,more and more cloud platforms provide a variety of efficient cloud services for people's work and life.People can facilitate their own life or work through these cloud services.For example,people can share their information or files through a public cloud storage platform so that others can get the file and work on them later.Nowadays it is very common to interact with one another through data exchange or file sharing to share information through file sharing among users.At the same time,storing data on a cloud storage platform or on an internal server so that other users can share the data means maintaining the data's security and integrity in the hands of the platform service provider's security policy.This means that the user's data security is completely dependent on the trust of third-party platform.Such a single trusted security strategy that relies on trust from a third-party certification body or a cloud-based security mechanism does provide some protection,but this moves all the danger to the user when the damage occurs Because of the asymmetric security information between user and platform,the source of the information controlled by the user is all maintained by a third-party platform,and the user can not verify it by themselves.Therefore,this paper applies the blockchain technology to the existing data sharing verifi-cation process.Most of the traditional solutions focus only on how to protect the consistency of the document and not to be tampered with.There is a problem with this approach.Most of these measures depend on the cloud platform system for its own maintenance.Once the cloud platform itself has been attacked,these security measures will no longer play any effective role.On the contrary,since the blockchain is a decentralized system,our verification system does not need to take extra computing resources of the original cloud platform to complete the verification independently.Based on the characteristics of the blockchain and the goals we need to verify,we have developed two block structures.By registering and querying identity blocks,a user can ensure that the user who receives the information to be shared can know whether the file he or she has received is the one that the original owner wants to share.Meanwhile,if the verification fails,the user can choose to register the corresponding content block,so that the user who receives the information obtains the content block through the query function and further merges to obtain the original data.In addition,the paper tests the verification by building a simulation system.Two sets of experiments were conducted by the test system for the common file sharing process and the tam-pered file sharing process.Respectively verify whether the identity block and the content block in the system can well achieve the purpose of the thesis.We also tested the effect of block length on system performance and found that the resulting overhead was negligible.Finally,by com-paring several of the major hash functions,we selected the one that best met our requirements in the paper.