Research On Blockchain Access Control Scheme Based On Smart Contract

In the era of rapid development of the network,e-commerce and e-medical have brought very convenient operation to the society.Access control is a security technology to prevent unauthorized entities from illegally obtaining secret resources.However,traditional access control schemes are centralized,which can easily lead to privacy leakage and single point bottleneck.Traditional access control schemes are lack of dynamic and fine-grained,which is no longer in line with the development trend of the current network.At the same time,with the rapid development of Internet of things(Io T),it has been widely concerned in recent years to realize intelligent medical by remote monitoring health data through Io T devices.However,due to the limited computing power and storage capacity of Io T devices,users' health data is stored in a centralized third party,and there are potential safety hazards.Meanwhile,users' health data has great research value for scientific research,so how to realize an intelligent medical scheme with privacy,security,self-control and decentralization of users' case information in distributed environment,coordinate the value sharing between scientific research and users' case information,and realize fair payment between them has also aroused widespread concern.So in order to solve the above problems,this paper uses blockchain and smart contract to build a new access control scheme,and the main research contents are as follows:(1)Role based access control(RBAC)which is a business dominant model is to separate subjects and permissions,and assign permissions by distributing the corresponding roles of users.However,the traditional RBAC is centralized,the role assignment of users is lack of fine-grained,and the assignment of roles and permissions is not dynamic,which is inconsistent with today's distributed and dynamic network architecture.Therefore,this paper proposes a flexible and dynamic RBAC improvement scheme DF-RBAC with smart contract.This scheme can realize the fine-grained allocation of user roles by resource owners,and also verify the assigned roles.Furthermore,the dynamic operation of users,roles and permissions and the security audit function of access activity log are realized through smart contract to ensure the security of the whole architecture.Through security and simulation analysis,this scheme is proved to be feasible.(2)In view of the above medical situation,this paper proposes a multi-blockchain intelligent medical data sharing scheme with fair payment based on smart contract,which combines traditional medical scheme with blockchain and cryptography technology,and designs three types of blockchain and six types of transactions.Nodes in different blockchains manage health data,key distribution,doctor diagnosis and scientific research reward through different types of transactions.Furthermore,smart contract is used to realize the reward qualification evaluation and fair payment.By introducing multiple medical blockchains,users' health data,doctors' diagnosis information and researchers' data utilization can not be deleted or tampered,so as to avoid medical disputes and realize paid sharing of users' health information.Security analysis and simulation results show that the multi-blockchain medical data sharing scheme is suitable for intelligent medical system.