Research On Privacy-preserving And Access Control Technology Of Internet Of Things Based On Blockchain

For the traditional centralized access control model of Internet of things(Io T),these models are generally based on trusted third party.There are some problems in the Internet of things,such as single point of failure and data tampering.In addition,Internet of things devices are also limited by power,memory,computing power and so on.This access control model based on trusted third party faces huge management and maintenance costs.With the rapid increase of Internet of things devices,this model can not meet the dynamic characteristics of Internet of things nodes joining or leaving at any time,which makes more and more Internet of things devices have the problem of low management efficiency.Therefore,the security and privacy of the Internet of things has always been a challenge for the development of the Internet of things.Access control technology is one of the most widely used security technologies,which can effectively protect the data security of the Internet of things and prevent the privacy leakage of users.The emergence of blockchain technology provides a new solution for the security and privacy problems of the Internet of things.Some solutions take advantage of the decentralized characteristics of blockchain to solve the single point of failure problem of traditional centralized access control.Some solutions use smart contract to solve the problem of Internet of things access control rights.Although these schemes achieve security to a certain extent,their availability and privacy are not fully utilized.Because the transaction data in the public chain is open and transparent,its access control data will still be exposed to the shadow of privacy disclosure.In order to solve the privacy problem in the access control scheme of the Internet of things based on blockchain,the main research work of this paper includes the following aspects:(1)in order to realize the security and credible access control of the Internet of things,this paper designs a mechanism to solve the privacy problem of the Internet of things access control based on blockchain.The mechanism designs two intelligent contracts in the existing framework:authorization contract and authentication contract.Through intelligent contract,decentralized and secure access control management can be realized.(2)In order to solve the privacy problem in the access control of Internet of things based on blockchain,this paper integrates zero knowledge proof and trusted execution environment technology to protect the sensitive information in the access control of the Internet of things on the basis of the existing privacy protection scheme.The zero knowledge proof technology is used to ensure the correctness of the transaction,and the trusted execution environment is used to protect the confidentiality and integrity of the intelligent contract.(3)In order to solve the efficiency of access management of Internet of things,this paper adopts role-based access control model and improves it.It can simplify authorization management and realize more flexible and accurate access control.(4)In order to prove the feasibility and effectiveness of the framework,this paper has carried out many experiments,and analyzed the efficiency of zero knowledge proof,throughput of transactions,and response time of Internet of things.The experimental results show that the framework has lower latency and higher throughput,which can achieve accurate and secure access control and ensure the high efficiency of access management.