Efficient Outsourced Data Access Control with User Revocation for Cloud-Based IoT

Data owners have benefited significantly from cloud computing for managing the numerous data produced by massive devices in various Internet of Things (IoT) applications, such as smart home and electronic healthcare. On the other hand, fine- grained access control on outsourced data is a big concern for data owners, after they lose physical control over their data. Key-policy attribute- based encryption (KP-ABE), which provides data confidentiality and fine-grained data access control simultaneously, can be naturally introduced in this cloud-based IoT paradigm. However, the primitive KP-ABE cannot achieve efficient data access control with flexible user revocation. In this paper, we propose an efficient and fine-grained data access control scheme based on the proxy re-encryption and key blinding techniques for cloud-based IoT. With the scheme, the decryption capability of misbehaving users can be efficiently revoked to prevent data disclosure. In addition, most of the costly update operations over ciphertexts and keys due to user revocation, are delegated to the cloud. Extensive experiment results demonstrate that our scheme is more efficient than existing solutions in terms of computation and communication overheads.