Circuit Cipher Text-Policy Attribute-Based Hybrid Cryptography With Demonstrable Delegation In Cloud Computing

In the cloud, for achieving access control and data security, the data owners could uses attribute-based encryption to encrypt the stored data. To reduce the cost, the users, which have a limited computing power, are nevertheless more likely to delegate the mask of the decryption task to the cloud servers. The result shows, attribute-based encryption with delegation come out. Still, there are some problems and questions regarding to previous related works. For example, during the delegation or release, the cloud servers could misrepresent or replace the delegated cipher text and respond a fake result with malevolent intent. As well as for the purpose of cost saving the cloud server may also fraud the eligible users by responding them that they are unworthy. Even, the access policies may not be flexible during the encryption. Since policy for general circuits are used to achieve the strongest form of access control, a construction to design circuit cipher text-policy attribute-based hybrid encryption with verifiable delegation has been developed. This system is mixed with verifiable computation and encrypt-then-Mac mechanism, the data confidentiality, the fine-grained access control as well as the correctness of the delegated computing results are well guaranteed at the same time. As well as this scheme achieves security against chosen-plaintext attacks under the k-multilinear Decisional Daffier-Hellman assumption. Moreover, this scheme achieves feasibility as well as efficiency.