Ciphertext Policy Attribute Set Based Encryption with One-Fold Data Access in Cloud

Cloud Computing is the most powerful paradigm in IT industry. Cloud users confide their valuable data’s in cloud. The major concern in cloud computing is the privacy of outsourced data’s. Several access control method has been employed to secure the outsourced data’s. Hierarchical Attribute Set Based Encryption (HASBE) extends Ciphertext Attribute Set Based Encryption (CP-ASBE) method with a hierarchical user structure to attain scalability, flexibility and fine grained access control of user’s data. Service provider has rampant storage capacity and computational power. But, it does not support constraint based verification system i.e. authorized user can access the data without any constraint. The proposed work provides high level of security for user data. Data is encrypted and managed by data owner which eliminates data replication in cloud environment. Here data consumer access resources directly from data owners. Attribute Authority plays the role of cloud service provider, trusted authority and domain authority. Attribute authority verifies the level of the data consumer and provides a packet with the level and key structure encrypted by notification key. Thus data consumer liaisons data owner with necessary information and obtain the data directly from the data owner.The proposed work is more secure and an effective way to access data in cloud environment without data replication. Also computation cost is reduced. User revocation is also effectively dealt by assigning multi-valued access expiration time.