Attribute based Encryption and Key Distribution for Secure Storage in Clouds

A new decentralized access control scheme is used for secure data storage in clouds that supports anonymous authentication. According to this scheme a user can create a file and store it securely in the cloud. Decryption will only work if the attributes associated with the decryption key match the policy used to encrypt the message. The cloud verifies the authenticity of the users without knowing the user’s identity before storing data. This scheme also has the added feature of access control in which only valid users are able to decrypt the stored information. This scheme is resilient to replay attacks and supports creation, modification and reading data stored in the cloud. The proposed scheme is resilient to replay attacks. In this scheme Secure Hash algorithm is used 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 cryptosystem is a probabilistic asymmetric algorithm for public key cryptography. Paillier algorithm is used for creation of access policy, file accessing and file restoring process.