Research And Application Of Attribute Based Encryption Based On Outsourced Computing

With the rapid development of cloud computing,the use of cloud server is more and more popular.Cloud storage server is one of the most widely used services at present,and its security has attracted much attention.Attribute-based encryption provides a secure and reliable encryption scheme for cloud storage,which provides a one-to-many fine-grained and controlled access policy on the premise of ensuring the security of data in cloud storage server.Attribute-based encryption has gradually become the most promising encryption system in cloud storage servers.However,because the computing method of attribute-based encryption consumes a lot of computing resources,it is difficult to complete the whole process of attribute-based encryption independently for the currently commonly used intelligent devices.Therefore,the outsourcing attribute-based encryption scheme is proposed.Its main idea is to use the outsourcing technology to reduce the user's local computing cost to constant level,so that the intelligent devices with limited resources can complete the attribute-based encryption.On the basis of outsourced attribute-based encryption,this paper proposes an outsourced attribute-based encryption scheme with other functions,and explores issues such as privacy protection in blockchain by the outsourced attribute-based encryption.The specific research contents are as follows:(1)Firstly,an outsourced attribute-based encryption scheme with keyword search is proposed.The scheme adopts the keyword search technology to speed up the user's data retrieval in the cloud storage server,and outsources the user's local operations to the cloud server in order to reduce the local computing burden of encryption and decryption.Finally,the dual system technique is used to prove the adaptive security of the scheme.(2)Secondly,a verifiable and fully outsourced attribute-based encryption scheme is proposed.In this scheme,cloud server is used to reduce the local computing burden of authority and decrypted users,and a secure outsourcing modular exponentiation method is used to reduce the local computing cost of encrypted users,and the correctness of the outsourcing encryption and decryption computing is verified.The scheme is selectively security under the determinative q-BDHE assumption.(3)Finally,an online/offline blockchain rewriting scheme with auditable outsourced computing is proposed.The scheme implements blockchain rewriting at the transaction level using a policy-based chameleon hash.At the same time,in order to reduce the local computing burden of encrypted and rewriting users,the scheme adopts online/offline technology to complete the encryption calculation,and uses the server to assist users to complete the rewriting operation.Finally,the scheme provides a function to limit the number of outsourced computing requests.