Research On Data Access Control Technology Based On Blockchain

With the advent of the era of big data,data has become an intangible asset with huge social and economic value.Access control technology is an important means to effectively ensure the security of data access by formulating relevant strategies to limit the scope of users’ access to data.However,with the rapid penetration of the Internet into all aspects of human society,data resources show the characteristics of distributed management,strong dynamics,and wide sources,etc.,while the traditional centralized access control technology has disadvantages such as poor scalability,lack of flexibility in a dynamic environment,and low authority management efficiency,which can no longer meet the needs of the current environment.Blockchain is a distributed management platform with the characteristics of decentralization,non-tampering,traceability,etc.It is of great significance for achieving efficient,dynamic,and fine-grained access control.Therefore,research on blockchain-based data access control technology is of great significance.The main research work of this paper includes:(1)Introduced the research background and significance of blockchain-based data access control technology,analyzed the current domestic and foreign research status of access control technology,attribute-based encryption,and user behavior-based trust evaluation,and summarized attribute-based access control technology,Trust evaluation,and related theories such as blockchain.(2)Aiming at the problem of the untrustworthy third parties in traditional attribute-based encryption schemes in the cloud storage environment,the cloud storage access control technology based on blockchain and attribute-based encryption is studied.The data owner stores the encrypted key in the blockchain through a smart contract and adds access time to the data.The existing information is pre-encrypted off-line to improve the encryption efficiency,and at the same time use an improved Bloom filter to hide the access strategy.The security analysis of the program is carried out from the aspects of anonymity,data integrity,access policy security,and collusion attacks,and the computational complexity is used to compare the encryption and decryption efficiency of the program and related programs.At the same time,experiments are designed for the program so that each The attributes have 5 values.The size of the attribute set in the ciphertext is increased from 5 to 50,and the comparison and analysis with the related schemes are carried out.(3)Aiming at the problem that the current access control scheme cannot dynamically adjust the access authority with time,the technical scheme of collaborative access control based on blockchain and trust evaluation is studied.When the data needed for trust evaluation is stored,the original data is stored in the out-of-chain database,and the corresponding hash value is stored on the chain.Use smart contracts to publish user trust thresholds and access strategies to the blockchain,and calculate information entropy to assign weights to attributes reasonably.After the user initiates an access,the sliding window and the time decay factor are used to calculate the user behavior trust value,combined with the recommended trust value to evaluate the user’s trust,and dynamically grant the user corresponding authority according to the trust value and the access strategy.Use Hadoop to carry out simulation experiments,so that 100 nodes are randomly distributed in the network,and each node completes at least 100 interactions,and compares the changes in trust value and the success rate of interactions with related solutions.The innovations in this article include:(1)Propose a technical solution for cloud storage access control based on blockchain and attribute-based encryption.This solution stores the attribute-based encryption key in the blockchain through a smart contract to realize distributed access control;in addition,the data is pre-encrypted in the offline phase to improve encryption efficiency;and the improved bloom filter is used The mapping between hidden attributes and access policies of the device.Security analysis and comparative experiments show that this solution has obvious advantages in encryption efficiency while ensuring security,and as the number of attributes increases,the advantages become more prominent.It is suitable for realizing efficient and flexible distributed access in a cloud storage environment.control.(2)Propose a technical solution for collaborative access control based on blockchain and trust evaluation.Use smart contracts to publish user trust thresholds and access strategies to the blockchain to achieve fine-grained access control;use sliding window mechanism and time decay factors to calculate user behavior trust values,To ensure the timeliness and credibility of the behavioral trust value in a dynamic environment.Experiments and related comparative analysis show that when the proportion of malicious nodes is 20%,the interaction success rate of this scheme is 8%-10%higher than that of the Smari model.It is suitable for effectively evaluating user behavior in a highly dynamic environment,and realizing dynamic authorization and fine-grained access control...