A Reliable and Secure Cloud Storage Schema Using Multiple Service Providers

Despite the many advantages provided by cloud-based storage services, there are still major concerns such as security, reliability and confidentiality of data stored in the cloud. In this paper, we propose a reliable and secure cloud storage schema using multiple service providers. Different from existing approaches to achieving data reliability using redundancy at the server side, we propose a reliable and secure cloud storage schema that can be implemented at the client side. In our approach, we view multiple cloud-based storage services as virtual independent disks for storing redundant data encoded using erasure codes. Since each independent cloud service provider has no access to a user’s complete data, the data stored in the cloud would not be easily compromised. Furthermore, the failure or disconnection of a service provider will not result in the loss of a user’s data as the missing data pieces can be readily recovered. To demonstrate the feasibility of our approach, we developed a prototype cloud-based storage system that breaks a data file into multiple data pieces, generates an optimal number of checksum pieces, and uploads them into multiple cloud storages. Upon the failure of a cloud storage service, the application can quickly restore the original data file from the available pieces of data. The experimental results show that our approach is not only secure and fault-tolerant, but also very efficient due to concurrent data processing. Keywords-Cloud storage; reliability; data security; erasure codes; cloud service provider; integer linear programming.