Decentralized Access Control with Anonymous Authentication of Data Stored in Clouds

We propose a new decentralized access control scheme for secure data storage in clouds that supports anonymous
authentication. In the proposed scheme, the cloud verifies the authenticity of the series without knowing the user’s identity before storing data.

Our scheme also has the added feature of access control in which only valid users are able to decrypt the stored information. The scheme prevents replay attacks and supports creation, modification, and reading data stored in the cloud. We also address user revocation. Moreover, our authentication and access control scheme is decentralized and robust, unlike other access control schemes designed for clouds which are centralized. The communication, computation, and storage overheads are comparable to centralized approaches.

• Distributed access control of data stored in cloud so that only authorized users with valid attributes can access them.
• Authentication of users who store and modify their data on the cloud. The identity of the user is protected from the cloud during authentication.
• The architecture is decentralized, meaning that there can be several KDCs for key management. The access control and authentication are both collusion resistant, meaning that no two users can collude and access data or authenticate themselves, if they are individually not authorized.
• Revoked users cannot access data after they have been revoked. The proposed scheme is resilient to replay attacks. A writer whose attributes and keys have been revoked cannot write back stale information.
• The protocol supports multiple read and write on the data stored in the cloud. The costs are comparable to the existing centralized approaches, and the expensive operations are mostly done by the cloud.