File Management And Access Control In Cloud Computing

Cloud computing, as a new and efficient computing model, represents a trend of large-scale, intensive and professional development in the IT field. Cloud computing technology has become one of the hot topics by the widespread concern and support in the IT field. Currently, the well-known IT companies at home and abroad are actively working to build their own business cloud computing system to provide users with a variety of applications and services, their actions also promote the vigorous development of cloud computing technology and related industries. However, the dynamic complexity of cloud computing environment, highly-concentrated resources and other characteristics raise new challenges to the cloud computing security. So how to achieve the goal of protecting user’s data security and privacy in the cloud computing environment becomes the urgent problems.This thesis analyzes the development of cloud storage and access control method of the current and points out the importances and difficulties of access control policy in cloud storage environment. Then we propose the new Hadoop-oriented file access control model for hybrid clouds. The model is divided into three components, the private cloud authorization platform, the local client agent which is running in a private cloud and the public cloud storage platform. In the private cloud authorization platform, we build the hierarchical access control model which bases on ABE and constant-size ciphertext in Hadoop cloud environment combining with the features of Hadoop and ABAC. The CP-ABE schema with constant-size ciphertext limits the ciphertext size and the time of encryption and decryption to a fixed value, but also supports inheritance authorization, reduces the burden and risks of a single authority, ensures fine-grained and flexible access structure while reducing heavy data transmission and computation overhead in the process of encryption and decryption and solves the problems of the limitation of cloud storage space. The local client realizes the goals of seamless connection between the public and private cloud storage systems as a proxy component. Finally, we combine the knowledge of software engineering to achieve the function of the model and test the completeness and robustness of our model.