Research Of Attribute-based Encryption With Attribute Change And Keyword Search

Attribute-based eneryption scheme is a research hotspol of cryptography in recent years,and attribute revocation is the extension and expansion of the attribute-based encryption.In practical application,the traditional single authority has the problems of low efficiency and low security,which makes people's research more and more oriented 10 multi-authority research.Multi-authority attribute-based encryption can improve the efficiency and the secure of single authority.However,almost ail the existing schemes with either single authority or multiple authority schemes do not achieve the function of keyword search,which makes it is difficult to search files for users.In this paper,we mainly research the attribtite-based encryption scheme with attribute cange and keyword search,the main results are as follows:1?We construct a searchable attribute-based encryption scheme with attribute revocation in cloud storage based on fine-grained.We add the access control into the search process,only when the search succeeds,cloud server can return the corresponding cipher text to the users.In this way.users can not download the files which they can not decrypt and save the spae.And our scheme supports multiple keywords search,which makes the scheme more practical.Under the assumption of decisional bilinear Diffie-Hellman exponent(BDHE)and decisional Diffie-Hellman(DDH)in the selective security model,we prove that our scheme is secure.2?We propose a privacy-preserving personal health record system using multi-authority attrihute-based encryption scheme with keyword search and attribute change,which improves the efficiency and security with a single authority,and our scheme supports dynamic change of user's attributes,including attribute revocation and attribute grant.And it doesn't need to update the cipher-text when attributes change for some users,which greatly reduces the compution load of the system.Besides,our scheme supporti the keyword search,which solves the problem that the search of users in a massive encrypted data.Furthermore,we use the part of decryption outsourcing technology to reduce the computation load of users.Under the assumption of decisional bilinear Diffie-Hellman(DBDH)in the selective security model,we prove that our scheme is secure.3?We construct a scheme that data owner can authorize the users to search.In the scheme,the data owner can authorize to the user without leaking key,authorized users can search the files he interested.In addition,the scheme also needs identity authentication.When the user interacts with the server,the server will verify its identity in order to prevent malicious behavior of illegal users.Finally,under the assumption of decisional Diffie-Hellman(DDH)in the selective security model,we prove that our scheme is secure.