An Efficient Access Control Scheme With Outsourcing and Attribute Revocation for Fog-Enabled E-Health

Fog computing is increasingly popular partly due to its capability to minimize data transfer and latency requirements, for example by moving some of the computational operations away from the cloud servers and closer to the users. To achieve fine-grained access control in fog-enabled application scenarios to guarantee data security and user privacy, one could use ciphertext-policy attribute-based encryption (CP-ABE). However, the lack of an effective mechanism to carry out access right revocation in conventional CP-ABE schemes limits the deployment of such schemes in practice. Thus, we propose an efficient CP-ABE scheme with attribute revocation capability, designed to construct a fine-grained access control system in fog-enabled E-health (referred to as AC-FEH). In our AC-FEH system, fog nodes undertake data encryption and decryption operations; thus, computational costs for data owners and users are minimized. In comparison to several other competing access control schemes based on CP-ABE, our AC-FEH system reduces the computational costs associated with encryption and decryption. We also prove the selective security of the underlying CP-ABE scheme under the intractability assumption of the $q$ -parallel BDHE problem.