Abstract: I propose a new decentralized access control technique for data securly storing in clouds that supports anonymous authentication. In the proposed technique, the cloud verifies the authenticity of sequence without knowing the users identification before storing files. My technique also has the extra feature of access control in which only authorised users are able to (decode)decrypt the saved data. This technique restricts the replay attacks and confirms the creation, modification, and reading data stored in the cloud. I also includes and supports user revocation. Moreover, my authentication and access control technique is decentralized and robust, unlike other access control techniques designed for clouds which are centralized. The communication, computation, and storage overheads are comparable to centralized approaches.

Keywords: Access control, authentication, attribute based signatures, attribute-based encryption, cloud storage, Information Security.