# Efficient and Secure Management of Medical Data Sharing Based on Blockchain Technology
## 1 Introduction  
In recent years, with the continuous improvement of human economic levels and quality of life, people's demand for medical health has been increasing. The medical industry has become one of the largest and fastest-growing industries in the world in recent years, especially with the spread of COVID-19 worldwide, which seriously threatens human life and health, affects global economic development, and leads to a significant increase in the proportion of countries' investment in the medical industry. Owing to the continuous updating of medical testing equipment, the continuous improvement of medical information systems, and the continuous development of artificial intelligence technology, the medical industry is developing towards intelligence, precision, and digitization. Medical data, as the foundation of smart medicine and precision medicine, plays a crucial role in biomedicine, new drug research and development, and prevention and treatment. However, medical data are affected by factors such as regional development, medical institutions' medical level, and informationization level, and they have characteristics such as scattered distribution, inconsistent specifications, and complex types, making it difficult to form unified and effective management and even more challenging to fully explore their potential value. To solve the problems in medical data management and better integrate medical data resources, a large number of medical data processing platforms [1,2] have emerged to facilitate data usage by medical institutions, research institutes, pharmaceutical companies, and others. These platforms collaborate with multiple hospitals and invite professionalmedical practitioners to annotate medical data, using professional medical data processing software, or designing new algorithms to process medical data. These processed data are widely used to establish medical models for real-world disease, which will aid in medical research [3], medical management [4], governmental public decision-making [5], and innovative drug development [6]. Although these platforms process the originally scattered and heterogeneous medical data, improving the value of medical data, it is difficult for the platforms to prove the authenticity of the data provided to customers, such as scientific research units, pharmaceutical companies, and government agencies, using existing medical data management platforms. The authenticity verification of medical data includes the authenticity verification of the original data, the new data generated during processing, the final data obtained, and the operations performed by the processors. In short, all contents related to medical data should be verifiable and traceable. The main objective of this paper is to address the issue of authenticity verification of medical data throughout the entire management and processing process, and to provide an efficient tracking and tracing solution. In recent years, blockchain technology has been successfully applied in data tamper-proofing, data integrity verification, and data security. Therefore, this paper proposes a blockchain-based medical data management platform to ensure the security and authenticity of medical data throughout the entire processing process. The blockchain records all the intermediate data generated during the process from raw data to final data, the operational behaviors performed by operators, and even the authorizations and query access operations performed. The immutability of the blockchain is used to ensure the authenticity of all records. The platform uses a method of storing data digests on the chain and storing medical data off the chain to reduce storage pressure on the blockchain. Smart contracts are used for trusted storage and authenticity verification of data. In particular, the platform provides a fast and efficient data provenance method.