A Secure Cloud Backup System with Assured Deletion and Version Control

TLDR

Cloud storage offers low‑cost, outsourced backup solutions, yet users must enforce strong security guarantees for their data. Fade Version is introduced as a security layer that protects cloud backups while preserving version control. The system eliminates redundant storage via standard version‑controlled design, applies cryptographic protection, and enables fine‑grained assured deletion of specific backup versions or files without affecting other shared data, as demonstrated in a prototype on Amazon S3. Empirical evaluation shows Fade Version incurs only minimal performance overhead compared to a traditional cloud backup service lacking assured deletion.

Abstract

Cloud storage is an emerging service model that enables individuals and enterprises to outsource the storage of data backups to remote cloud providers at a low cost. However, cloud clients must enforce security guarantees of their outsourced data backups. We present Fade Version, a secure cloud backup system that serves as a security layer on top of today's cloud storage services. Fade Version follows the standard version-controlled backup design, which eliminates the storage of redundant data across different versions of backups. On top of this, Fade Version applies cryptographic protection to data backups. Specifically, it enables fine-grained assured deletion, that is, cloud clients can assuredly delete particular backup versions or files on the cloud and make them permanently inaccessible to anyone, while other versions that share the common data of the deleted versions or files will remain unaffected. We implement a proof-of-concept prototype of Fade Version and conduct empirical evaluation atop Amazon S3. We show that Fade Version only adds minimal performance overhead over a traditional cloud backup service that does not support assured deletion.