Research On Trusted Sharing Technologies For IoT Data Based On Lightweight Blockchain

With the popularity of wireless ubiquitous interconnection capability,massive heterogeneous IoT applications are facing increasingly serious data security problems,while providing users with convenient information services.Cloud computing,data mining and other technologies solve the data sharing and storage problems of resource-constrained IoT devices by providing remote resource sharing pools.However,since the user will lose the physical control of data after the data is put on the cloud,and the lack of centralized management of the cloud platform leads to frequent problems such as single point of failure and data tampering,which brings serious data leakage and asset loss.Therefore,how to achieve trusted authorization and security audit in the process of IoT data sharing has become an important challenge to be solved.Research shows that the current security problems in the process of IoT data sharing are mainly reflected in the confusion of trust relationship among massive heterogeneous IoT nodes,the ambiguity of data flow and authority granting records,and the lack of safe and reliable key management and certificate distribution mechanism.Therefore,the formation of a system that provides complete trust management of IoT nodes,credible storage of data sharing records and secure granting of data access authority is an urgent problem nowadays.As a data and value exchange mechanism which can work in an open network environment,blockchain can provide a distributed trust and authority management platform for IoT data sharing.However,given the characteristics of the IoT environment such as device heterogeneity and resource constraint,the traditional blockchain system cannot be directly deployed for IoT data applications,and the existing lightweight blockchain methods suffer from the problem of blindly sacrificing security and decentralization to improve system performance.Therefore,through asynchronous scheduling of transaction tasks,the thesis rationally optimizes the resource allocation structure of the blockchain system,builds a IoT data protection mechanism based on lightweight blockchain,and deposits the trust relationship and data rights information of IoT nodes on chain.And combined with distributed file system and smart contract technology,it can also check the consistency and integrity of data.The main content of the thesis is as follows:(1)A trusted sharing method for IoT data based on proxy re-encryption is proposed,which addresses the problems of confusing node trust relationship management and difficult data rights control in heterogeneous IoT environment,divides the security domain of isolated system,anchors node trust relationship hierarchically,realizes dynamic access and exit of nodes based on blockchain,and combines distributed file system for blockchain storage expansion.The trustworthy storage of IoT data and full-process traceability of cross-domain data sharing records are finally realized.Especially for the problems of high operation cost of traditional public key cryptosystem and the keys of resource-constrained device are easily leaking,a controlled data transferring algorithm based on KIE-PRE is designed by combining key isolation technology and proxy re-encryption algorithm;smart contracts are used to complete the on-chain re-encryption calculation to ensure that the original plaintext and private key information is hard to be leaked while achieving a fair and trustworthy data permission granting process;through The key isolation technology,the algorithm regularly updates the round key,which reduces the impact time range of key leakage,then provides a lightweight key distribution and deployment mechanism for IoT applications.(2)An asynchronous transaction submission mechanism based on multichannel cache is proposed,namely the MCC-ATS model.To address the problems of poor system resource utilization,blind sacrifice of system security and decentralization,and insufficient deployment network scalability of existing lightweight blockchain technologies,the transaction submission operation is asynchronized using multi-channel caching technology and asynchronous Byzantine fault-tolerant consensus protocol,allowing IoT nodes to write transactions into the classification cache network autonomously and asynchronously,thus supporting high concurrency and low response.Moreover,a database slicing technique is used to cache heterogeneous IoT transactions in a distributed cluster to achieve highly available local memory space expansion and network communication fault tolerance;a parameter tuning and priority scheduling strategy is designed based on queuing model and threshold encryption algorithm to achieve the best balance between security and performance and overhead while improving system resource utilization.(3)A lightweight blockchain-based data sharing system for the IoT is designed and implemented.First,the overall design of the system is introduced,and the core requirements and business processes of the system are described from three perspectives:system architecture design,data structure design,and functional module design.Then,we introduce the specific implementation technology of the system,and implement and test the main functional modules of the system,such as node identity management,data authority management and cipher data storage.The results show that the system can realize the identity authentication of IoT nodes and data sharing records storage and traceability,and the built-in controlled data transferring algorithm and asynchronous transaction submission mechanism can effectively optimize the system resource allocation,which can be applied to the IoT scenario with limited heterogeneous resources and can acquire good performance.