Hierarchical Attribute-Set Based Encryption for Scalable, Flexible and Fine-Grained Access Control in Cloud Computing

Cloud computing has emerged as the most influential paradigm in recent years. The new computing technology requires users to entrust their data to the cloud provider, which leads to security issues on the outsourced data. In order to achieve scalable, fine-grained and flexible access control for cloud computing, we extends Ciphertext-Policy Attribute-Set-Based Encryption (CP-ASBE) by building in a hierarchical structure to obtain Hierarchical Attribute-Set-Based Encryption (HASBE) for cloud computing. The proposed scheme inherits flexibility in supporting compound attributes, and achieves scalability due to the hierarchical structure. More efficient user revocation is achieved because of the use of attribute-set which allows us incrementally update user's expiration time. We analyze the proposed scheme, and it is showed that the scheme is not only efficient and flexible in dealing with access control for cloud computing, but also has the same security as CP-ASBE.