Research On Big Data Access Control On Block Chain

With the continuous development of the Internet and its own increasing complexity,the privacy protection of Internet big data has attracted more and more attention.In order to fully realize the value of data,it is necessary to circulate and share the data among all kinds of scattered data sources,but it will inevitably affect the security of the original data management and increase the risk of data sharing.Take the medical and health big data of residents to see a doctor as an example.On the premise of big data sharing,how to protect the patient's privacy information such as medical history,medical record information and operation situation from the threat of privacy disclosure.For privacy protection,the perfection and maturity of access control technology is very important.For the current problems,most of them adopt the attribute access control model with visitors,data resources,data providers and context as the basic elements,which has higher flexibility and extensibility in strategy,and is also extensive in the application scenarios of the model.Compared with the role access control model,the model can achieve more fine-grained data sharing and access control.However,there are many problems such as dynamic update of access policy,multi-authorization center scheme,secure storage of access policy and distrust of third party.Block chain is a distributed database technology based on digital encrypted currency technology,and the application of block chain technology to big data sharing,access control mechanism and user data privacy protection is a new research direction in recent years.The most fundamental characteristic of block chain is the public authentication mechanism,which is decentralized,all nodes can participate in decision making,and the distributed accounting system.Because block chain technology uses digital authentication mechanism and data encryption mechanism,the characteristics of the two mechanisms make it non-tampering and traceability.The unique data processing method of block chain has become the key factor to play its own value in the application of various industries.Combining access control with block chain can solve the problem of data sharing and dynamic update of access policy in untrusted environment.Aiming at the above problems,a hierarchical access control model based on block chain and policy is proposed: BP-ABAC.The access control strategy is stored in the block chain by intelligent contract,and the access control strategy is classified in the contract design.The user obtains the access rights of the corresponding policy set according to the level evaluation.Access resource permissions are obtained when the request attribute matches the policy in the policy set.The main contents of this paper are as follows:(1)Model framework design: first,a decentralized,tamper-proof and traceable big data security data sharing model is established.Based on the attribute access control model,block chain technology is introduced.To meet the requirements of current access control over time,access control policy contract security and policy retrieval efficiency.(2)Intelligent contract module design: the access control strategy is stored in the block chain by intelligent contract,and the access control strategy is classified in the contract design.The user triggers the contract state machine according to the grade evaluation to obtain the corresponding policy access rights.When the attribute request matches the policy in the policy set,the user gets access to the resource.(3)Policy hierarchical design: each policy has different trusted values for different entity attributes,and the trusted values are adjusted according to the access behavior of nodes.The final trusted value of each policy is determined by its own initial and historical trustworthy values.It is used as the mapping basis of policy confidence level.(4)Analysis of simulation results: under the condition of different policy scale,the average value is obtained in many experiments,and compared with the existing access control model,and the policy query efficiency,policy matching success rate and model security analysis of the BP-ABAC model are judged.The experimental results show that the model can grant the corresponding access control permissions according to the access requests of different users,and improve the time efficiency and accuracy of the access control process.In addition,the security and privacy of the access policy storage and data sharing interaction process are improved.