| In 2016,the European Telecommunications Standards Institute(ETSI)expanded the concept of Edge Computing from Mobile Edge Computing to multi-access Edge Computing.Moreover,edge computing is extended from telecom cellular network to other wireless access network so that various heterogeneous devices can join the network and provide computing services.Although the robustness of edge computing network is enhanced,edge nodes joining the network are vulnerable to attack and thus face security threats.However,whether it is mobile edge computing or multiaccess edge computing,the correctness of the calculation results obtained by end-users from edge service nodes is not taken into account in the existing researches,especially in multi-access edge computing,which is easy to be attacked,and the reliability of edge node service cannot be fully guaranteed.In this thesis,block chain technology and zero-knowledge proof technology are introduced into edge computing network,aiming to verify the correctness of edge node calculation results without leakage of calculation results without excessive consumption of network computing resources,so as to improve the security of edge computing.The research contents are as follows:Based on blockchain,smart contract and zero-knowledge proof,a new security edge computing scheme is proposed in this paper.This scheme utilizes the decentralized trust characteristics of blockchain to realize the trust of edge service nodes.However,since the protection of service reliability achieved by redundant computing of blockchain nodes is not fully applicable to compute-intensive edge computing scenarios,this paper innovatively adds zero-knowledge proof technology into the scheme.The edge service node will process the task request under the chain without broadcasting to the blockchain network,and the zero knowledge proof intelligent verification contract will be invoked on the chain to verify the execution result,so as to improve the service reliability of edge node.Taking TSP(Travelling Salesman Problem)as a demonstration example,this paper carries out a practical test on the physical demonstration platform,and makes a comparative analysis with the scheme of realizing edge node reliable service directly through the redundancy computing of blockchain nodes.The test results show that for a single blockchain node,the gas consumed by using both blockchain technology and zero-knowledge proof technology is only 1/150 of that consumed by using blockchain technology directly.The scheme proposed in this paper achieves the goal of improving the security of edge computing while only bringing relatively small resource consumption.In order to meet various delay requirements of edge computing services and further realize secure edge computing,this paper designs a hierarchical Reputation algorithm based on zero-knowledge proof,ZKPREPUTATION.Based on the verification of task processing results with zero-knowledge proof,the algorithm comprehensively considers many factors,such as time,error times and computation amount,to manage the credit value of service nodes.For edge service nodes with high reputation,end users can directly trust their calculation results without waiting for the feedback of the call result of zero-knowledge proof to verify the contract,so as to reduce the impact of the delay caused by the addition of blockchain and zero-knowledge proof technology.The simulation test results of ZKPReputation algorithm show that when the end user chooses the service node with high Reputation value according to the results of ZKP-Reputation algorithm to directly trust its processing results,the total time consumed by 20 calculations is accumulated.Only 27.5%of the total time when zKPReputation algorithm is not used.Therefore,the addition of the credit algorithm effectively reduces the impact of the addition of blockchain and zero-knowledge proof.According to the proposed security edge calculation scheme and ZKP-Reputation algorithm,this paper builds a physical demonstration and verification platform composed of 15 nodes.Cosmos was used to provide the underlying blockchain service for the system,Truffle was used to implement the credit contract and zero-knowledge proof to verify the deployment of smart contract,and blockchain nodes were interconnected through Intranet penetration to complete test preparation.After the platform was built,the function of the system and the resource consumption of zero knowledge proof were tested to ensure the availability of the system.The test results show that the application of block chain technology and zero-knowledge proof technology to edge computing network can ensure the reliability of computing results of edge service nodes,and realize the privacy protection of computing results. |
