Multiple Attribute Authority based Access Control with Anonymous Authentication using User Revocation in Decentralized Cloud

Cloud computing is the delivery of computing services over the Internet. The cloud computing model allows access to information and computing resources from anywhere and at any-time. Here the information security and data privacy are the major concerns over the cloud storage system. Normally access control in cloud are centralized in nature. In centralized system only single key distribution center is available and use the same key for encryption and decryption and does not support anonymous authentication. So to avoid the leakage of user personal details Multi-authority attribute based decentralized access control schemes are used for data storage. In the proposed scheme, attribute authority issues all attribute keys to the user without knowing the user personal details using Cipher-text policy attribute based encryption. In addition to that user revocation mechanism is used to activate and deactivate the users using Diffie-Hellman Merkle key exchange algorithm. Revoked users are maintained in the user revocation list and make publicly available in the cloud. User revocation scheme will decide which user should be permitted to access data or removed from cloud. The data access privilege will be depending upon the behaviour of users in cloud server.