Efficient CP-ABE Scheme Resistant to Key Leakage for Secure Cloud-Fog Computing


 With the evolution of the Internet, people’s lives are growing increasingly intelligent, and massive amounts of data are also generated. The combination of cloud computing and fog computing can store and process it efficiently. However, a new and urgent challenge has emerged about how to ensure that data in cloud and fog nodes are accessed securely. In order to address this issue, we propose an efficient anti-key leakage CP-ABE (EAL-CP-ABE) scheme based on cloud-fog computing. In our scheme, we achieve the identity tracing of the authorized user who leaked the private key by means of white-box tracing and the maximum number of user accesses. Meanwhile, we design a reward and punishment mechanism which rewards those with a good reputation and revokes authorized users who have exceeded the access limit or sold private keys to further reduce the possibility of key leakage. Due to limited local resources, we use fog nodes to achieve outsourced decryption of ciphertext. In addition, the detailed security analysis is provided to prove that the EAL-CP-ABE scheme is IND-CPA secure and traceable based on the hardness assumptions. Finally, we demonstrate that the EAL-CP-ABE scheme is efficient through the performance analysis.
 
