File history facilitates the creation of a timeline of attributed events, which is crucial in digital forensics. Timestamps play an important role for determining what happened to a file. Previous studies into leveraging timestamps to determine file history focused on identification of the last operation applied to a file. In contrast, in this paper, we determine all possible file histories given a file’s current NTFS timestamps. That is, we infer all possible sequences of file system operations which culminate in the file’s current NTFS timestamps. This results in a tree of timelines, with root node the current file state. Our method accounts for various forms of timestamp forgery. We provide an implementation of this method that depicts possible histories graphically.

File carving is a data recovery technique used in many investigations in digital forensics, with some limitations. Especially JPEG files are difficult to recover when fragmented, because they consist almost entirely of large blobs of highly compressed entropy-coded data, with no clearly discernible structure.