A novel proxyoriented public auditing scheme for cloudbased medical cyber physical systems Abstract   Cloudbased medical cyberphysical system (MCPS) is attracting more and more attention, since it can break through the limitations of time, space and object, and allow doctors to make accurate telemedicine diagnosis for patients. However, since medical information is directly related to the safety of patientsxe2x80x99 lives and property, it has become an urgent problem to ensure the integrity and availability of medical data. To solve the above problems, many integrity auditing schemes have been proposed in recent years. Unfortunately, most existing schemes have security flaws or poor performance. Very recently, Zhang etxc2xa0al. proposed an identitybased proxyoriented auditing scheme for checking the integrity of medical data, and claimed that their scheme was secure. However, we find that their scheme fails to achieve its purpose since it is vulnerable to the user impersonation attack and misusing delegation attack. we propose a new proxyoriented public auditing scheme to fix the security vulnerabilities. Security analysis and performance evaluation demonstrate that our proposed scheme greatly reduces the communication and computation costs while ensuring a novel security level. Compared with Zhang etxc2xa0al.xe2x80x99s scheme, our scheme is more suitable for applications in cloudbased MCPS.

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.