Main Article Content
Security and privacy are very important issues in cloud computing. In existing system access control in clouds are centralized in nature. The scheme uses a symmetric key approach and does not support authentication. Symmetric key algorithm uses same key for both encryption and decryption. The authors take a centralized approach where a single key distribution center (KDC) distributes secret keys and attributes to all users. A new decentralized access control scheme for secure data storage in clouds that supports anonymous authentication. The validity of the user who stores the data is also verified. The proposed scheme is resilient to replay attacks. In this scheme using Secure Hash algorithm for authentication purpose, SHA is the one of several cryptographic hash functions, most often used to verify that a file has been unaltered. The Paillier crypto system is a probabilistic asymmetric algorithm for public key cryptography. Pailier algorithm use for Creation of access policy, file accessing and file restoring process.