A RAID-Based Secure and Fault-Tolerant Model for Cloud Information Storage

Cloud computing allows for access to ubiquitous data storage and powerful computing resources through the use of web services. There are major concerns, however, with data security, reliability, and availability in the cloud. In this paper, we address these concerns by introducing a novel security mechanism for secure and fault-tolerant cloud information storage. The information storage model follows the RAID (Redundant Array of Independent Disks) concept by considering cloud service providers as independent virtual disk drives. As such, the model utilizes multiple cloud service providers as a cloud cluster for information storage, and a service directory for management of the cloud clusters including service query, key management, and cluster restoration. Our approach not only supports maintaining the confidentiality of the stored data, but also ensures that the failure or compromise of an individual cloud provider in a cloud cluster will not result in a compromise of the overall data set. To ensure a correct design, we present a formal model of the security mechanism using hierarchical colored Petri nets (HCPN), and verify some key properties of the model using model checking techniques.