Research On Access Control Technology And Its Application Based On Blockchain

The booming development of smart devices has brought vitality to the Internet of Things,and provided convenient and diversified life for people.Also,it brought some new challenges.In the information society,data interaction is necessary.In order to guarantee the security of data,access control is an important mechanism.Most of traditional access control mechanisms are not reliable enough,because they serve centralized systems.In addition,when applied to large scale systems,they might be lack of flexibility and granularity,difficult to manage.Therefore,traditional access control mechanisms are not suitable for applying to large-scale systems directly.We need a more reliable,flexible and fine-grained access control mechanism.Blockchain combines many cryptography techniques such as hash function,asymmetric encryption and digital signature.It also implements smart contracts.Because of its characteristics of decentralization,openness,transparency,and immutability,blockchain fits into the distributed Internet of Things environment,considered as a promising decentralized solution that can effectively strengthen the security protection of access control mechanisms.This paper studies the access control mechanism based on blockchain,and the main work is as follows:First of all,this paper proposes a fine-grained multi-authority access control scheme based on blockchain.On the basis of attribute-based access control(ABAC)model,a distributed system is constructed by using the blockchain and multiple attribute authorities that jointly maintain the blockchain to avoid the single point of failure.Referring to the idea of secret sharing,the processes of authority management,attribute authorization and data sharing are designed and implemented by using attribute-based access policy and smart contract.The system model and workflow of the scheme are introduced in detail,and the contract algorithm is described.This scheme is flexible,dynamic and fine-grained.The security analysis shows that the proposed scheme is safe and can resist multiple attacks.The simulation results show the performance and feasibility of the proposed scheme.Secondly,in view of the privacy leakage problem existing in the disclosure of blockchain transaction data,this paper proposes an access control scheme with privacy protection of blockchain data.It combines attribute-based encryption and searchable encryption.The transaction data in the blockchain are encrypted and security indexes are generated according to access policies and extracted keywords.Only the user whose attributes match the access policy can successfully find matching transaction information and decrypt it by constructing a search token with the correct keyword.This scheme not only protects the privacy security of blockchain data,but also realizes the fine-grained access control and the quick search of ciphertext for authorized users.The security analysis and experimental results show that the scheme is safe and efficient.