Abstract
Cloud storage is one of the most promising services of cloud computing. It holds promise for unlimited, scalable, flexible, and low cost data storage. However, security of data stored at the cloud is the main concern that hinders the adoption of cloud storage model. In the literature, there are many proposed mechanisms to improve the security of cloud storage. These proposed mechanisms differ in many aspects and provide different levels of security. In this paper, we evaluate five different mechanisms for supporting the security of the cloud storage. We begin with a brief description of these mechanisms. Then we evaluate these mechanisms based on the following criteria: security, support of writing serializability and reading freshness, workload distribution between the client and cloud, performance, financial cost, support of accountability between the client and cloud, support of file sharing between users, and ease of deployment. The evaluation section of this paper forms a guide for individuals and organizations to select or design an appropriate mechanism that satisfies their requirements for securing cloud storage.