ACHIEVING AVAILABILITY AND DATA INTEGRITY PROOF IN HIERARCHICAL ATTRIBUTE ENCRYPTION SCHEME USING HYBRID CLOUD

Abstract

It has been widely observed that the concept of cloud computing has become one of the major theory in the world of IT industry. Data owner decides to release their burden of storing and maintaining the data locally by storing it over the cloud. Cloud storage moves the owner’s data to large data centers which are remotely located on which data owner does not have any control. However, this unique feature of the cloud poses many new security challenges. One of the important concerns that need to be addressed is access control and integrity of outsourced data in cloud. Number of schemes has been proposed to achieve the access control of outsourced data like hierarchical attribute set based encryption [HASBE] by extending cipher-text-policy attribute set based encryption [CP-ABE]. Even though HASBE scheme achieves scalability, flexibility and fine grained access control, it fails to prove the data integrity in the cloud. Hence integrity checking concept has been proposed for HASBE scheme to achieve integrity. Though the scheme achieves integrity it fails to provide the availability of data to the user even when fault had occurred to data in the cloud. However, the fact that owner no longer have physical possession of data indicates that they are facing a potentially formidable risk for missing or corrupted data, because sometimes the cloud service provider deletes the data which are either not used by client from long-time and which occupies large space in the cloud without the knowledge or permission of data owner. Hence in order to avoid this security risk, in this paper we propose a hybrid cloud concept. Hybrid cloud is a cloud computing environment in which an organization provides and manages some internal resources and external resources. A hybrid cloud is a composition of at least one private cloud and at least one public cloud. This concept provides the availability and data integrity proof for HASBE scheme.