Secure Deletion for a Versioning File System

We present algorithms and an architecture for the secure deletion of individual versions of a file. The principal application of this technology is federally compliant storage; it is designed to eliminate data after a mandatory retention period. However, it applies to any storage system that shares data between files, most notably versioning file systems. We compare two methods for secure deletion that use a combination of authenticated encryption and secure overwriting. We also discuss implementation issues, such as the demands that secure deletion places on version creation and the composition of file system metadata. Results show that new secure deletion techniques perform orders of magnitude better than previous methods.