Research On Data Confirmation Time Based On The Combination Between Internet Of Things And Blockchain

Blockchain not only improves the security of Internet of Things,but also brings low efficiency of data transmission.Because the blockchain using POW(Proof of work)consensus algorithm and before using the data in block,blockchain needs to wait for a period of confirmation time after block is mined to ensure the security and efficiency of data.So the blockchain has insufficient processing ability when dealing with mass data's inflowing in IOT.The use of GHOST protocol in Ethereum greatly improves the mining efficiency based on POW.Therefore,this paper chooses Ethereum to research the shortest confirmation time of the data in blockchain and the IOT application can confirm the data in the block as soon as possible under the premise of ensuring certain data security.This paper analyzes the influencing factors of the shortest confirmation time——the minimum confirmation block number and the actual confirmation block number.The minimum confirmation block number is related to the fork probability of the blockchain and the probability of the increase of the confirmation block.In this paper,a mathematical model is constructed to analyze the node which had received the block in order to solve the above factors.Finally,the simulation experiment is carried out by using Matlab simulation tool.Two groups ofexperiments were designed to obtain the shortest confirmation time in different network environment and application requirements.The results show that increasing data confirmation time can significantly improve data security and when the ratio of attack node is 15%,30%,and 45%,the application sets confirmation time to 47.4seconds,79.05 seconds and more than 173.95 seconds can keep the data unusable at less than 5%.