A BlockchainBased DataSharing Architecture In the new global economy, data has become an important resource. Sharing data can bring their value into full play. Before the process of data sharing, due to the limitations of personal storage resources, data owners usually upload data to a public cloud server for storage. However, the method of storing data to the cloud cannot guarantee that stored data has not be accessed when its owner is unknown, and such unauthorized access behavior often results in a loss of interest to the data owner. To solve this problem, in this paper, a blockchainbased data sharing architecture is proposed. The architecture uses the way to store metadata in isolation from raw data to avoid the possibility of user data being stolen and to ensure information security in the process of data sharing. At the same time, it describes a blockchain network model for data sharing to ensure that there is no association between unrelated entities. On the other hand, it also provides a way for data owners to distribute finegrained access control permissions based on specific scenarios.

Design of a Secure Medical Data Sharing Scheme Based on Blockchain With the rapid development of technologies such as artificial intelligence, blockchain, cloud computing, and big data, Medical Cyber Physical Systems (MCPS) are increasingly demanding data security, while cloud storage solves the storage problem of complex medical data. However, it is difficult to realize data security sharing. The decentralization feature of blockchain is helpful to solve the problem that the secure authentication process is highly dependent on the trusted third party and implement data security transmission. In this paper, the blockchain technology is used to describe the security requirements in authentication process, and a network model of MCPS based on blockchain is proposed. Through analysis of medical data storage architecture, it can ensure that data canxe2x80x99t be tampered and untrackable. In the security authentication phase, bilinear mapping and intractable problems can be used to solve the security threat in the authentication process of medical data providers and users. It can avoid the credibility problem of the trusted third party, and also can realize the ?thyc10?u003etwoway authentication between the hospital and blockchain node. Then, BAN logic is used to analyze security protocols, and formal analysis and comparison of security protocols are also made. The results show that the MCPS based on blockchain not only realizes medical treatment data sharing, but also meet the various security requirements in the security authentication phase. In addition, the storage and computing overhead costs is ideal. Therefore, the proposed scheme is more suitable for secure sharing of medical big data.