Research On Blockchain-based Medical Data Sharing Scheme

In recent years,medical information technology has been developing rapidly,meanwhile,medical data sharing is of irreplaceable significance for improving the level of health services as well as reducing cost of patients.Some problems in medical data sharing which cannot be ignored can be seen as follows.Firstly,considering that medical data contains some personal health information which is privacy-sensitive and the data could be accessed without obtaining any consent or legal authority because they were stored in semi-trusted cloud servers.Secondly,because of the internal faults and possible adversarial attacks,medical data are in risk of being modified or even being deleted.Lastly,accessing medical data requires verifying related permission which costs time and may cause latency and reduce efficiency.In addition,how to motivate people to share medical data requires indepth thinking.Blockchain could be considered as a distributed ledger technology.It could effectively solve the problem that medical data may be modified or even being deleted by using its temperresistance and traceability.At the same time,it could be used to implement trusted value delivery without relying on any trusted third party,helping to reduce transaction cost and improve transaction efficiency,providing a good platform for motivating users to share medical data.Recently,some blockchain-based medical data sharing schemes have been proposed,however,most of them have obvious flaws(e.g.access control is inefficient and privacy preservation related to transaction data is leaked).In this paper,we research on these issues.Our contributions can be seen as follows.In order to cope with the privacy preservation with regard to transaction data,we propose a scheme based on homomorphic encryption.With this scheme,only nodes who are the two sides of transaction could access the plaintext of transaction and the unrelated nodes can merely verify the correctness of transaction.We propose some potential application scenarios of our scheme.In addition,with the security analysis,it is proved that the scheme can guarantee the confidentiality,validity and tamper-resistance of transaction.We propose a blockchain-based medical data sharing scheme.Symmetric encryption is used to ensure the confidentiality of medical data.Blockchain is used to ensure the integrity of medical data.Dynamic cryptographic accumulator is utilized to provide a flexible and lightweight access control policy.We also conduct a security analysis on the above three aspects of this scheme.On top of the two schemes mentioned above,we design and implement a blockchain-based data sharing system in Fabric.We build a modular blockchain network and utilize Mongo DB to simulate the cloud server.The functions include uploading data,downloading data and initiating transactions,etc.We test the functions including uploading data,downloading data and initiating transactions through experiments and prove the feasibility of the system.