When cryptography meets storage

Abstract

Confidential data storage through encryption is becoming increasingly important. Designers and implementers of encryption methods of storage media must be aware that storage has different usage patterns and properties compared to securing other information media such as networks. In this paper, we empirically demonstrate two-time pad vulnerabilities in storage that are exposed via shifting file contents, in-place file updates, storage mechanisms hidden by layers of abstractions, inconsistencies between memory and disk content, and backups. We also demonstrate how a simple application of Bloom filters can automatically extract plaintexts from two-time pads. Further, our experience sheds light on system research directions to better support cryptographic assumptions and guarantees.