DepSky

TLDR

The growing use of cloud storage for critical data such as medical records, biomedical datasets, power‑system histories, and financial information raises concerns about reliability and security. DepSky is designed to enhance the availability, integrity, and confidentiality of cloud‑stored data by encrypting, encoding, and replicating it across a cloud‑of‑clouds. The system was deployed on four commercial clouds and evaluated with PlanetLab clients from multiple countries. Experiments showed that DepSky improved perceived availability and access latency compared to single providers, while keeping costs at most twice that of a single cloud, a reasonable trade‑off for the added benefits.

Abstract

The increasing popularity of cloud storage services has lead companies that handle critical data to think about using these services for their storage needs. Medical record databases, large biomedical datasets, historical information about power systems and financial data are some examples of critical data that could be moved to the cloud. However, the reliability and security of data stored in the cloud still remain major concerns. In this work we present DepSky, a system that improves the availability, integrity, and confidentiality of information stored in the cloud through the encryption, encoding, and replication of the data on diverse clouds that form a cloud-of-clouds. We deployed our system using four commercial clouds and used PlanetLab to run clients accessing the service from different countries. We observed that our protocols improved the perceived availability, and in most cases, the access latency, when compared with cloud providers individually. Moreover, the monetary costs of using DepSky in this scenario is at most twice the cost of using a single cloud, which is optimal and seems to be a reasonable cost, given the benefits.