Security And Privacy Protection Method For Stream Data Based On Blockchain In Cyber-physical System

Cyber-physical systems(CPS)is essentially a distributed control system.It uses sensors,actuators,and other IoT devices to tightly integrate the information network world and the physics world.Through the human-computer interaction interface to realize the interaction with the real physical world,and using the networked space to control the physical entities in a remote,reliable,real-time,secure,and collaborative manner.However,with the widespread use of CPS,a large number of cyber-physics system devices and control systems are based on open Internet connections,and security and privacy protection problems are gradually appear.Especially,in the transmission and storage process of dynamic and difficult information physics systems stream data will face new security threats.During the transmission process,the attacker will try to intercept the system power consumption and timing behavior and other attributes to analyze the transmitting stream data to obtain sensitive information.At the storage layer,a large amount of information physics system stream data is collected and stored by a centralized server,but these servers may be damaged by external attacks and cause data loss and damage,so that the entire information physics system crashes and goes down,which seriously affects the robustness of the information physics system.The profit-seeking nature of third-party cloud server providers is also one of the reasons for data leakage or tamper with.In addition,the cyber-physical system,as a distributed control system,the attacker can obtain the network topology relationships by deploying malicious nodes to steal the relationship between the parties of the cyber-physical system.Based on these problems,this dissertation takes the stream data of the cyber-physical system as the research object,and proposes a security and privacy method based on the blockchain that can protect the stream data of the cyber-physical system during transmission and storage.The main work of this dissertation includes the following points:(1)Firstly,this dissertation use the stream data of the cyber-physical system as the transactionmedium of the blockchain,use the sender of the data as the initiator of the transaction,thereceiver of the data as the receiver of the transaction,and store the stream data in the globalledger of the blockchain to ensure the availability and immutability of the data.Secondly,inorder to better protect the privacy and security of cyber-physical system stream data,thisdissertation uses the blockchain network as the transmission channel of cyber-physical systemstream data.In order to avoid attackers stealing network topology by deploying maliciousnodes and other means,this dissertation adds onion network privacy protection mechanisminto the blockchain network.The receiver can use the transaction records that have been storedin the blockchain ledger to verify whether the data has been distorted during transmission.(2)In order to improve the security and privacy of the stream data stored in the blockchain,thisdissertation analyzes the main privacy protection mechanisms of blockchain transactions andledgers,and designs a special blockchain privacy based on the idea of group signatures.Protection mechanism which can not only protect the privacy of blockchain transaction data,but also provide a reasonable supervision mechanism for supervision and managementdepartments.(3)In order to protect the identity privacy of the initiator of the blockchain transaction,thisdissertation improves a group signature scheme based on previous research,so that it can beapplied in a decentralized environment,and the improved group signature scheme is used asthe signature scheme for blockchain transactions.In order to protect the privacy of blockchaintransaction initiators and digital assets,this dissertation designs a group confidentialtransaction scheme combining confidential transactions and group signatures.This schemeensures that verifiers can verify effectiveness of the transactions without knowing the accountof the transaction initiator.In order to protect the address privacy of digital asset recipients,this dissertation combines the group signature and an anonymous address protocol to designa supervisable semi-anonymous address protocol.(4)Through the random oracle model and elliptic curve discrete logarithm problem analyze thecorrectness,anonymity,traceability and others of the method proposed in this dissertation.The efficiency of the improved group signature scheme and other group signature schemesare compared under the same conditions,and it is concluded that the group signature schemeof this dissertation has a more friendly supervision mechanism at the expense of smallefficiency.The group secret protection transaction is compared with other mainstream secretprotection transactions to prove the availability.The blockchain privacy protection mechanismof this dissertation is simulated and implemented in the Hyperledger Fabric platform,and theadditional overhead of the mechanism is tested at the nodes.