Research On Access Control Strategy Management Of Internet Of Things Based On Blockchain

With the rapid development of information technology,the Internet of Things,as a technology with great potential for wide application,plays an important role in the development of science and technology all over the world.Due to the huge volume of IOT devices,a large amount of data is generated in the application process.These data including the privacy of users and devices need to be carefully protected through security protection measures to prevent huge losses caused by privacy data leakage.Access control mechanism is an important way to protect the secure and orderly use of Internet of things data.As the core part of access control mechanism,access control strategy is the fundamental to ensure that the access control model can effectively prevent malicious access.Therefore,how to ensure the confidentiality of access control policy information to resist various security risks and reduce the risk of privacy disclosure is the primary problem to be solved in the process of access control policy management.Blockchain is a new technology in the field of digital currency encryption.Its characteristics of immutability,traceability and decentralization provide a new solution to the security storage problem of access control strategy.Blockchain can be used to realize the distributed management of access control policies,so as to realize the flexible control of access control policy data.However,with the continuous growth of access control policy data,and once the blockchain data is stored on the chain,it can,t be deleted,which not only increases the storage pressure of blockchain,but also reduces the management,interaction and execution efficiency of access control policy.To solve the above problems,this paper studies the access control policy management of the Internet of things from the aspects of access control model construction,policy data storage optimization and policy management intelligent contract design.The main research work and results are as follows:(1)A trust-based access control model for the Internet of Things is constructed.Aiming at the problems of insufficient dynamic access control authorization and insufficient granularity of authority division in the traditional role-based access control model(RBAC),an access control model based on trust is proposed.The user trust evaluation is introduced into the access control model to reflect the change of user access behavior through the change of user trust value,and adjust its access rights at the same time.In addition,the access control permissions are more finely divided,so that the level of protected resources in the security level is more detailed,so as to better prevent users from accessing resources beyond their level.(2)The storage and management method of Io T access control policy based on DAG blockchain is proposed.For the storage security of key data such as access control policy information,the decentralized characteristics of blockchain are used to ensure the safe storage of data.However,due to the defects of blockchain's own performance,it can,t meet the data storage with high interaction frequency of access control policy information.Therefore,the directed acyclic graph(DAG)is introduced to improve the traditional blockchain structure,and a DAG based blockchain is constructed.The traditional blockchain is reconstructed in the storage layer,consensus layer and contract layer,so as to improve the interaction efficiency of the blockchain.The experimental results show that the DAG based blockchain system reduces the average block out time by 4.88 s,improves the system throughput by86.8%,and can effectively improve the interaction efficiency of blockchain storage resources.On this basis,a storage and management method of Internet of things access control policy based on DAG blockchain is proposed to realize efficient storage and security management of policy.(3)Smart contracts for the management of access control policies for the Internet of Things are designed.In order to complete the distributed access control decision,a series of operations such as decision authorization of access control process,setting and storage of access control policy,execution of access control policy and management of user information are completed through the smart contract running on the blockchain,so as to design and deploy the smart contract with corresponding functions into the DAG blockchain network.Complete the function operation through the automatic and orderly operation of the smart contract,and test the related functions of the smart contract.The experimental results show that each contract can run normally and stably,and has obvious advantages in system CPU,memory consumption and average execution time compared with other smart contracts.Therefore,the design contract in this paper performs better in performance.The blockchain based Internet of things access control policy management model proposed in this paper enhances the application of blockchain technology in Internet of things data storage and protection to a certain extent.In addition,it realizes the secure access and access control policy management of Internet of things data information based on blockchain,it provides strong theoretical and practical support for the development of safe and reliable Internet of things applications and the design of innovation platform in the field of Internet of things data security,and has certain practical significance and application value.