A. Research background As the development and progress of computer technology, the Internet has been becoming an integral part of one’s life. The user-demands of internet use have not only limited to browse the portal but also to the development of Internet application services resulting in explosive growth of internet data. Facing massive data, the ISPs needs more processing units and storage devices to ensure the regular operation of the corresponding system functions. However, it is still an urgent issue to solve for ISPs that the high cost of memory devices, personnel management, and equipment maintenance. To reduce these problems, cloud computing came into existence. Compared to the traditional computing model, the cloud computing model distributes computing tasks on a large number of computers due to the explosive growth of internet data today. This model allows users to allocate resources to the required on demand and access the computer and storage systems on demand, providing fast, efficient, and inexpensive computing power that maximises users’ storage service needs. As a result, the data computing model has changed from the traditional computing model to the large data cloud computing model. At present, as an emerging network storage technology extended and developed by cloud computing concepts, cloud storage technology is essential with the widespread popularisation of Cloud Computing. Cloud storage technology uses cluster applications, network technology or distributed file systems, etc. Cloud storage technology makes full use of the existing different storage devices in the system to provide users with data storage, data retrieval, data backup and other functions through application software ran by a user terminal. B. The purpose and significance of the study More and more individual and business users focus on cloud storage and transfer data to cloud storage with the development of cloud storage. Using cloud storage services requires users to store the data in the cloud storage device, instead of storing data on a PC as traditional computing model does. There must be a outsize risk because users do not know the boundaries of the cloud storage system, do not know whether the storage devices were shared, and can not ensure the availability and reliability of storage devices. The data of the user may be stored in a shared cloud storage system instead of storing in devices of cloud service provider. So users cannot control data security to ensure the confidentiality and integrity.