Research On Optimizing The Data Convergence Security Mechanism Of The Internet Of Thines Based On Blockchain

In the Internet of things,the data aggregation mechanism is the basis for the formation of data network and the guarantee for the development and application of the Internet of things.However,the security of data aggregation mechanism is affected by many factors.Among them,the security defects in the process of data transmission and storage greatly threaten the data security and reduce the reliability of the Internet of things system.COAP is a kind of network transmission protocol applied to restricted networks and nodes.It optimizes the restricted M2M(machine to machine)scenario,and describes and discovers the resources in the restricted Internet of things environment using the core link format.Based on the COAP protocol,the resource directory entity RD is proposed by the coal working group.The resource directory has the resource description of other terminal restricted nodes.It supports other terminal restricted nodes to discover,register and operate the registered resources on the resource directory,so as to realize resource discovery and access.COAP and its resource directory play the function of data transmission and storage in the process of data aggregation of the Internet of things,and are an important part of the Internet of things system.The resource directory lacks security-related content,so there are also some security issues.One of the problems is that it is vulnerable to attacks and lacks a device authentication process.Some attacking nodes may pretend to be restricted devices to attack the resource directory,or pretend to be a resource directory to continuously interact with the device,occupying the device's resources,and causing network paralysis;The second problem is the insecurity of data storage.The computing and storage capabilities of sensor devices in a restricted network are very limited,and may be stolen during the data transfer process.In addition,the centralized data management model also has huge risks.Once the storage platform is compromised,In the event of an attack,data may be damaged or lost.In view of the above problems,this paper attempts to provide solutions,through the introduction of blockchain technology and data aggregation mechanism security semantic expansion,to achieve device authentication and secure storage.The research content and work of this article are as follows:First,I studied the security issues of the data aggregation mechanism of the Internet of things and completed the security semantic expansion.Through the research on the resource directory,we found out its problems.Based on the Semantic Internet of Things,security semantics are added to the CoAP resource directory,and the SC attribute is used to provide security capabilities for the resource directory.On this basis,the at attribute is extended,and different security levels are identified according to different numbers to improve the safety performance of system.At the same time,a semantic model is established based on medical scenarios and combined with security semantics to provide a reference for the implementation of the system.Second,I established a blockchain-based IoT authentication and storage model to complete security analysis.On the basis of RD,a blockchain proxy module is added.The proxy authenticates the device's identity,and the Internet of Things data is stored in the blockchain.By analyzing the underlying principles of the blockchain and the system authentication mechanism,a formal verification of the security performance of the system is carried out.Third,the blockchain module and the coding extension of security semantic attributes were completed in the open source platform Californium,and related functions and performance tests were carried out.Based on the Californium platform,the Java language is used in conjunction with Ethereum and smart contracts to implement system functions.Simulate medical scenarios in the notebook experimental environment for functional testing and performance testing,compare with the original resource directory and draw relevant conclusions.