The Research And Application Of Efficient Hidden Policy Attribute-based Encryption

With the development of cloud computing technology and the increasingly perfect cloud infrastructure,more and more enterprises,individuals choose to store private data such as documents and information in the public cloud provided by third-party companies.The first requirement is security for public cloud that is regard as an open environment.However,due to the openness of the public cloud and the diversity of users,the traditional encryption method is difficult to adapt to ensuring the user's privacy and security fields.Therefore,a new type of encryption method Attribute-based encryption(ABE)came into being.Attribute-based encryption combines the idea of access control and encryption.The user's identity is used as the encrypted attribute,and the attribute is used to define the access policy.Therefore,attribute-based encryption has one-to-many encryption characteristics and fine-grained access control features.The attribute-based encryption method is based on elliptic curve,which contains a large number of complex operations,especially pairing operations.At the same time,in the classic attribute-based encryption algorithm,the user's access policy is passed in the form of plain text,which is not suitable for scenarios with higher security levels.Therefore,how to improve the computational efficiency of attribute-based encryption and how to hide the user's access policy have attracted scholars' attention.Through a lot of literature research,this thesis analyzes the specific algorithms and principles of the existing attribute-based encryption schemes.On the basis of these classic algorithms,the internal research of the algorithm,combined with the advantages of cloud computing,has achieved the following research work:(1)This thesis proposes a verifiable hidden policy attribute-based encryption scheme based on outsourced decryption.Compared with the classic attribute-based encryption scheme,this scheme hides the user's access policy and ensures the privacy of the user.At the same time,considering the issue of efficiency,the solution borrows the idea of outsourcing decryption and outsources complex calculations to a third-party cloud server,which greatly reduces the user's local overhead.In terms of outsourced decryption,a testing algorithm was introduced to optimize the traditional outsourced algorithm,which accelerated the computing efficiency of the outsourced server.(2)Although the outsourced decryption-based verifiable hidden policy attributebased encryption scheme improves the user's decryption efficiency and the efficiency of third-party cloud servers,it introduces additional encryption parameters,causing the problem of excessive encryption time.Therefore,this thesis proposes a strategy of hidden attribute-based encryption based on offline encryption.The offline encryption algorithm combines the idea of preprocessing,and the necessary parameters for user encryption are prepared before the formal encryption algorithm runs,which reduces the time consumption during the user encryption algorithm and improves the efficiency of user encryption.(3)Based on the above two schemes and VANET environment.We discuss and propose an efficient information transmission system based on VANET,and gives the system architecture and security analysis.