Research On Attribute Access Control Model Of IOT Based On Blockchain

Most of the traditional Io T access control models are built based on centralized trusted entities,which have problems such as opaque decision-making process,poor dynamic scalability,and poor autonomy of device owners,and cannot meet the complex computing environment of Io T with lightweight,massive heterogeneous and dynamic access.With the development of blockchain technology,it provides a new solution for Io T access control to achieve secure and efficient data interaction and access decision because of its decentralized,tamper-proof and traceable characteristics.Therefore,based on the ABAC model,this paper proposes a blockchain-based access control model for Io T attributes.By combining blockchain technology and Io T access control,decentralized fine-grained access is achieved to solve the problems of centralized decision making,lack of trust and audit and supervision of traditional Io T access control system.The simulation experiments show that the control model,decision mechanism,and contract escalation scheme proposed in this paper are suitable for access control requirements in complex Io T systems.The specific research in this paper focuses on the following points:(1)A blockchain-based Io T access control model is proposed to transform each functional execution point in the ABAC model into a corresponding smart contract,and a data structure for non-contract-like transactions is proposed to solve the problem that attributes or policies cannot be updated.By combining Bloom filters into smart contracts,the query efficiency of attributes is improved;finally,a comparison test is conducted to show that the query efficiency of Bloom filter-based smart contracts is higher.(2)Adopting NGAC,the next-generation access control standard in the ABAC framework,an IOT access control decision mechanism based on the NGAC specification is proposed.The NGAC multi-strategy graph is constructed with the typical IOT application of smart agriculture scenario as a case;the decision algorithm of NGAC multi-strategy graph is given by combining the depth-first traversal algorithm of the graph;the efficient lookup algorithm is given by combining the index table and Bloom filter for two common access requests.The time complexity of the lookup for the two types of access requests is given and compared with other literature for analysis,and finally verified by experiments.(3)To address the situation of business upgrade of smart contracts transformed by ABAC model,a lookup table-based on-chain upgrade scheme USC-LT for smart contracts is proposed,which divides the original contract into three contract modules:agent contract,data contract and logic contract,and solves the problem that the contract cannot be upgraded after deployment.Firstly,the data structure of contract-like transactions is given,and the specific algorithm of contract module is given with the example of registered contract in smart agriculture scenario;finally,the cost of original contract deployment,the extra cost generated by contract module deployment,and the cost saved by upgrading the contract are given through experiments,which show that using USC-LT model for upgrading contract effectively reduces the deployment cost of contract.