Building Trust in Storage Outsourcing: Secure Accounting of Utility Storage

We are witnessing a revival of storage service providers in the form of new vendors as well as traditional players. While storage outsourcing is cost-effective, many companies are hesitating to outsource their storage due to security concerns. The success of storage outsourcing is highly dependent on how well the providers can establish trust with their consumers. While significant work has been done to ensure confidentiality, integrity, and availability of data, a practical solution for accounting of outsourced storage is still at large missing. This paper presents Saksha, a secure accounting system that enables automated and verifiable metering of the resources utilized by the consumers. A provider that includes Saksha as a part of its storage service can prove to its customers the amount of resources utilized by them. As a result, Saksha will help to enhance trust by preventing any inflation or deflation of the service usage. Saksha is not restricted to any particular pricing model; it can be applied to the popular pay-per-use pricing model for utility storage as well as many of its variants. In addition, it can be used by the consumers to periodically evaluate their usage and reassess their outsourcing requirements. Saksha is developed such that it can be layered on the top of networked file systems. Our performance results demonstrate that Saksha is efficient and can be used in practice.