Research On Attribute-based Encryption In Data Sharing In Cloud

In recent years,with the rise and development of the concept of big data,more and more industries and fields have begun to focus on the mining and use of big data,aiming at using big data to promote the progress of the industry.However,big data may contain personal privacy information when published and shared in the cloud,which may cause the leakage of personal privacy,then causes damage to personal interests,and even threaten life safety.In the process of big data sharing,access control technology is generally used for data stored in the cloud to control the sharing of data.The ciphertext-policy attribute-based encryption(CP-ABE)technology can provide fine-grained access control,so it has received widespread attention and the study.However,the traditional CP-ABE scheme has the risk of privacy leakage.In the traditional CP-ABE scheme,the access policy is not hidden in the ciphertext.When sensitive information is included in the access policy,private information may be leaked.At the same time,the decrypted data obtained by the user in the traditional CP-ABE scheme is original.When the user illegally uses the data,it may also cause the leakage of private information.Therefore,this thesis focuses on the above-mentioned problems in the traditional CP-ABE scheme.The main research contents are as follows:(1)A policy hidden CP-ABE scheme based on homomorphic encryption is proposed.The scheme introduces homomorphic encryption into the CP-ABE scheme,constructs an attribute matching mechanism based on homomorphic encryption,uses composite order bilinear groups to construct a policy hidden scheme based on access tree,and effectively realizes the fully policy hidden scheme.Compared with the existing policy hidden scheme based on access tree,our scheme achieves lower computational cost on the basis of ensuring fully policy hidden.(2)A plaintext perturbation CP-ABE scheme combining random response is proposed.The scheme uses k-RR technology as the specific implementation technology of random response,which can be applied to an access tree with a simple structure,to construct a plaintext perturbation scheme based on the access tree structure.Compared with the existing plaintext perturbation scheme that combining random responses,the access structure constructed by our scheme is simpler and has a lower computational cost.(3)A medical cloud data sharing system is proposed in which the policy hidden CP-ABE scheme based on homomorphic encryption and the plaintext perturbation CP-ABE scheme combining random response are applied to the system by constructing a hierarchical HK-ABE scheme.The system is built to verify the feasibility and applicability of the two schemes proposed in the article in practical application.