| With the development of science and technology,a large amount of data is generated every day,and the value of all kinds of data is becoming more and more prominent,and the demand of different individuals for data trading and sharing is becoming more and more urgent.The value of data applications in social management,research and teaching,sales and marketing,and life and entertainment is becoming more and more obvious.Data trading and resource sharing promote the circulation of data,eliminate data silos,and increase the value of data.In addition,data trading and sharing has strict requirements for data security and other aspects.Users on both sides of data trading and sharing want to provide better protection of privacy while sharing data transactions.However,the current traditional centralized data trading and sharing platform has challenges such as the risk of retaining user transaction data and the lack of privacy protection for users,which hinder the trading and sharing of data.The advantages of blockchain technology can solve the main constraint problems faced by current data transaction sharing,and can ensure fairness while achieving privacy protection and improving sharing efficiency.In this paper,we analyze the existing security problems in data trading and sharing and propose improvement solutions.The main research of this thesis includes the following:(1)To address the problems in data trading,this thesis proposes a blockchain-based data trading scheme.Firstly,by analyzing the existing data transaction model and discovering the data security and transaction protection problems therein,a third-partyfree data transaction platform is established by using blockchain;AES and improved homomorphic encryption technology are combined to protect users’ data security,and encrypted data are stored to a Inter Planetary File System(IPFS);secondly,inadvertent transmission protocol,two-way identity authentication,zero-knowledge proof and other security verification for data transactions;finally,using security analysis and efficiency analysis to prove that this scheme has higher security and transaction efficiency.(2)To address the data sharing security issue,this thesis proposes a new data sharing scheme based on blockchain and edge computing.First,this scheme adopts ciphertext policy-based attribute-based encryption(CP-ABE)and proxy re-encryption to encrypt the shared data,which ensures data confidentiality and efficient fine-grained access control;it adopts edge nodes for attribute authorization scheme in attribute authorization,which effectively alleviates the problem that centralized-based attribute authorization is detrimental to data sharing;second,by using edge nodes to apply to the blockchain The data is sent to IPFS for distributed storage,and the distributed storage address is stored in the blockchain.When users request data from the distributed storage system,the edge nodes will authenticate the users and authorize the attributes and record the results on the chain,and the data is decrypted first by the edge nodes for preliminary decryption,which improves the decryption efficiency of users;finally,security analysis and comparison of different schemes are conducted to it is shown that the proposed scheme can achieve data security protection,key verifiability and resistance to conspiracy attack,and then the proposed scheme is proved to be secure under the chosen plaintext attack by the random prediction machine model. |
