Research On Technologies Of Data Access Control In Cloud Storage

With the development of the Internet,the need of massive data storages and complicated calculations can be seen everywhere in life,though it is difficult to gather both efficient computing and safe storages for normal users.In this case,cloud computing is widely used because of its powerful storage capacity,efficient computing capacity and data sharing.Attribute-based encryption scheme is the most widely used encryption method in cloud computing for safe and convenient fine-grained access control.However,due to the complex encryption and decryption algorithm,attribute-based encryption scheme cannot play its advantages on resource-limited mobile devices.Based on this situation,this thesis focuses on a secure and efficient cloud computing access control scheme especially for resource-constrained devices,which can not only enable users to flexibly formulate access policies,but also solve the problem of key abuse in traditional attribute-based encryption schemes.The main researches of this thesis are as follows:(1)Aiming at the access control scheme on resource-constrained mobile devices,an efficient and low computational cost online/offline encryption outsourcing decryption access control scheme based on attribute-based encryption is proposed in this thesis.In the encryption part,the complex bilinear pair calculation is performed when the device is offline.In the decryption part,most of the complex calculations are outsourced to the efficient cloud server.Compared with the traditional schemes,the computing cost on the user's device is reduced and the decryption time is shorter according to outsourcing decryption.In addition,the scheme proposed with multi-attribute reduces more computing cost for users because the conversion key is generated by attribute authority.(2)In view of the situation that users may reveal decryption keys on purpose,a multi-attribute online/offline encryption,outsourcing decryption,traceable access control scheme based on the encryption scheme in(1)is proposed.The scheme can trace and recognize the users for revealing the private key through the decryption key.This scheme does not need to maintain a user table,and does not need redundant storage overhead,which ensures the security and reliability of access control and greatly improves the utilization rate of resources in access control.(3)A smart community with smart cloud distribution system based on attribute-based encryption access control is designed in this thesis.Users upload the data and share it on the cloud platform.Only specific users with allowed access policy attributes can obtain the data.Besides the good performance of the system on mobile terminals is displayed in the thesis.