Study On Data Security And Privacy Preserving Mechanism Of Internet Of Things Based On Consortium Blockchain

With the development of Internet and emerging information technology,the data processing of Internet of Things is becoming more and more automatic and intelligent.The difficulties in the research of Internet of Things data security and privacy preserving technology lie in the lack of a reliable trust platform to achieve interoperability,the need for lightweight cryptographic algorithms for low-energy devices,and protecting identity privacy but difficult to supervise.In every field of data circulation,the consortium blockchain can be combined with cryptographic technology to ensure the security of data,establish public,transparent and traceable data supervision,provide flexible and elastic user privacy,and realize the value circulation of Internet of Things data.This dissertation mainly studies the data security and privacy preserving scheme of Internet of Things based on consortium blockchain,including system model design,security model construction,security proof,performance evaluation and simulation analysis.The security model is the important cornerstone of scheme construction.In order to meet the challenges brought by data security and privacy preserving technology in special scenarios,cryptographic schemes based on consortium blockchain are designed by using cryptographic primitives such as aggregate signatures,ring signatures and provable data possession,and their applications for Industrial Internet of Things,Internet of Things and digital twin are discussed.This dissertation has completed the following achievements:First,the aggregate signature is a kind of digital signature with compression property.It integrates multiple signatures into a short signature,which can reduce the computation cost and communication cost in data transmission.In the existing security model of privacy preserving aggregate signature,there is no construction of resisting the coalition attacks and traceability.In the Industrial Internet of Things environment,the attacker controls some anonymous sensors and initiates the coalition attack,which exists in the real scene.For regulatory needs,the security model should also consider how to trace malicious signers.Therefore,an anonymous traceable aggregate signature scheme based on consortium blockchain is designed for Industrial Internet of things.According to the assumption of difficult computational Diffie-Hellman problem,the unforgeability is proved in the random oracle model.Performance analysis and experiments in Hyperledger Fabric platform show that the scheme makes an effective balance between security,privacy and efficiency.Second,the privacy model of existing data sharing schemes does not fully consider the behavioral privacy of data users.For benefit,the malicious cloud may build the behavior database of data users.This dissertation analyzes the security requirements of private data sharing onto user wearable devices,and constructs a new privacy-preserving private Internet of Things data sharing scheme by using consortium blockchain,deniable ring signature,Monroe and digital rights management technology.The security model includes attributes such as anonymity,unforgeability,resisting profile building and non-frameability.Under the assumption of computational Diffie-Hellman problem,the scheme is provably secure.Through the performance analysis,the case demonstration of smart watch in Alibaba Internet of Things platform and experiments on Hyperledger Fabric platform,the scheme is easy to implement and has the practical application value.Finally,the first synchronized provable data possession scheme based on consortium blockchain is studied for the security of digital twin space.The synchronized tags constructed in the scheme have homomorphism,which can aggregate verification and accelerate the process of data integrity checking.For the security model of digital twin system as a special application,the synchronized tag can also verify the time state of the data,so as to detect whether the data state has changed,which can prevent the poisoning attack of the analysis data.Under the assumptions of RSA and knowledge of exponent,the scheme is provably secure.Performance analysis and simulation experiments in Hyperledger Fabric platform show that the scheme is efficient and the delay caused by synchronization is reasonable.