Research On Internet Of Things Access Control Technology Based On Blockchain

In the IoT system,securing access control is the most basic and important part.In the discussion of security,the combination of blockchain and Internet of Things has become a hot trend.Cornell's Lightweight Scalable Blockchain project proposes a comprehensive layered framework based on blockchain technology and optimizes for blockchains including lightweight consistency and distributed trust algorithms.The project focuses on the realization of low-power blockchain IoT architecture.By optimizing the consensus algorithm to meet the needs of the Internet of Things,and not considering the IoT access control and the bottleneck storage resource bottleneck,it is still subject to the performance of the blockchain itself is limited.This paper absorbs the idea of hierarchical management of IoT devices in the LSB project,and implements access control and data flow through the ABAC(Attribute Based Access Control)model on the blockchain for the extensive access control requirements of the Internet of Things.Separation.The main work of this paper is as follows:(1)Optimized the LSB project layering model,and refined the layered Internet of Things structure that connects resource-constrained devices into the blockchain.Devices classified into high,medium,and low-level devices can access the blockchain in different ways.Separately undertake different functions such as maintenance network,proxy gateway,and upload data to meet the low-power and expandable requirements of the Internet of Things.(2)Optimized the structure of ABAC under the blockchain,and designed four types of intelligent contracts to implement ABAC access strategy.It mainly includes policy management points,policy decision points,policy enforcement points and attribute authority.Attribute authority and policy management points respectively implement automatic loading of attributes and policy information,and policy decision points implement dynamic access decisions.The strategy implementation point uses the Whisper protocol to reduce the impact of low blockchain transaction performance on the overall system.(3)Combine the IPFS file storage technology,store the resource files such as device firmware in the IPFS,and realize the separation of the data flow and the control flow.IPFS can be connected to smart contracts.The automatic mapping of hash values and resources enables secure storage of files and reduces the storage pressure of blockchains.