Privacy Preserving Data Storage And Cross-domain Sharing Scheme

Along with the rapid development of technologies such as mobile computing and cloud computing,and the rapid spread of the social network,more and more users have changed their roles from former consumers of information services to data producers.As the dramatic increase in the magnitude of user-generated content and the uploading and downloading of massive data resources between different security domains,how to ensure the effective data sharing between different systems while fully guaranteeing the security of users' privacy data has become a high-profile subject.To ensure the security of data,users usually upload and share the data after encrypted and the Attribute-based Encryption schemes and Ciphertext-based Retrieval came into being.Through the Ciphertext-based Retrieval,users can retrieve the cipertext in the same way as the plaintext.This method is convenient for users to protect the data security without losing the convenience of usability.And through the Attribute-based Encryption,users were converted from previous role-mapping sets to a single attribute-definition set,which greatly improves the fine-grained access control,and converts the sharing system from one-to-one sharing to one-to-many.In terms of data storage,this paper introduces a form in which binary trees are nested in a B+ tree as a high-efficiency retrieval structure and utilizes a combination of the hybrid index structure and the sort algorithm to achieve efficient ciphertext-based keyword sorting and indexing system.This paper also researches the specific environment of the Connected Vehicular Cloud Computing.And the division of process in the system is fully updated with the concept of Roadside Unit.In this paper,data should be safely stored on the cloud,and we utilize large numbers of roadside units which are closer to the vehicle system to allocate most of the calculations to them,allowing the vehicle nodes to deliver the keyword information to the nearest one at any time even under high-speed motion conditions.The roadside unit,which is a data processing operation performed by a static device,solves the problems of network instability,data packet loss,and transmission delay under high-velocity motion of the vehicles.And we prove both higher security and efficiency through the security analysis and performance simulation.In terms of data sharing,to enable the data owners to effectively manage the identities of visitors,this paper chooses the Ciphertext Policy Attribute-based Encryption scheme.In most current researches,only the attribute values are hidden.In practice,the attribute name also contains a lot of valuable information.If only the attribute values are hidden,it still may expose the user's privacy information.To solve the above problems,this paper proposes a cross-domain data sharing scheme,which applies a fully hidden access structure CP-ABE scheme to cross-domain identity authentication and access control mechanisms.It removes the issuance of user attribute certificates to improve the existing access control mechanism.And it introduces the Domain Location System and Cross-Domain Attribute Management System to ensure the user's attribute information is fully hidden during the entire program.This paper also utilizes a Garbled Bloom filter and a Linear Secret Sharing Scheme.And it combines a Bloom filter and XOR-secret sharing to fully hidden the policy utilizing the query ability of the Bloom filter and hidden ability of XOR-secret sharing.The scheme is proved higher security.