Study And Design On Multi-authority Centers Attribute-based Encryption

With the development of Internet technology and the arrival of the big data era,cloud servers have been widely used by the industry due to their powerful computing capabilities and huge storage space.Cloud computing has become an inevitable trend of the development of the Internet agein the future.While the cloud server provides convenient services for the end users,the security problems brought by the cloud server itself cannot be ignored.Attribute-based encryption is a kind of cryptosystem with a threshold access control strategy,which can effectively solve the problem of share data storage security in the cloud.In this paper,aiming at the security and privacy of sensitive data stored on the cloud server,the linear secret sharing scheme access structure and proxy re-encryption technologyare used.With the help of PIS protocol and logical binary tree,three access control schemes based on attribute encryption under different application scenarios are designed.In order to solve the problems of collusion attack and multi-domain shared data in the multi-authority centers attribute-based encryption scheme,a multi-domain access control scheme based on multi-authority attribute encryption for cloud storage is presented.In the proposed scheme,the central authority does not participate in the generation process of user's key,and it can effectively avoid the attackbetween users and authorized institutions.To achieve the single domain and the multi-domain data sharing,the cloud server utilizes the linear secret sharing scheme and the proxy re-encryption technique to re-encrypt the data files.To solve the problem of how to flexibly and efficiently change user access rights under the premise of ensuring cloud data security,an attribute-based encryption access control scheme for multi-authorization centers and permission changes ispresented.In the scheme,the attribute private key is jointly generated by different attribute authorization centers,and it can effectively prevent the collusion attack.It uses hash function to acquire the keys of nodes in binary tree,and it utilizes the smallest key of root nodes to serve as group keys corresponding to every attributes.Finally in order to achieve the fine-grained attribute changes,it uses group keys to update user private key and ciphertext.Aiming at how to make users get a good online experience in the social platform and ensure the security of the user's sensitive data,a multi-authority centers attribute-based encryption scheme with friendsmatching mobile social networks is proposed.In the scheme,the user uses the symmetric encryption algorithm and the attribute encryption mechanism to encrypt the file to be uploaded and store it in the cloud.The system judges the responding user group in advance according to the value of the attribute similarity,and pushes the responding user who meets the requirement to the user who initiates the friend,which enables users to make friends in a short period of time.Users are deleted by friends or leave the system,using proxy re-encryption technology to ensure that this user will not be able to continue accessing data files and using decryption outsourcing services effectively reduces the user's computing tasks.