Triviback: A Storage-Efficient Secure Backup System

The importance of frequent backups is uncontroversial. Their creation is simpler than ever today thanks to widespread availability of cheap cloud storage. Common backup solutions, however, tend to be either insecure, inflexible or inefficient in typical backup scenarios. In this paper, we present triviback, a lightweight and almost trivial, yet powerful solution for outsourcing backups to untrusted cloud storage. Based on recent research results on secure data de-duplication, triviback combines strong confidentiality, authenticity and availability guarantees with flexibility and efficiency in terms of low storage and communication costs: Triviback supports efficient preservation of many backup states with storage costs comparable to state-of-the-art version control systems-while supporting full storage reclamation on deletion of arbitrary backup states. We discuss its security, publish an implementation and perform an extensive evaluation of storage and communication costs.