FRAGMENTED JPEG FILE RECOVERY USING PSEUDO HEADERS

Overview & Synopsis

Many techniques have been proposed for file recovery, but recovering fragmented files is still a challenge in digital forensics, especially when the files are damaged. This chapter focuses on JPEG files, one of the most popular photograph formats, and proposes techniques for recovering partially-damaged standalone JPEG fragments by reconstructing pseudo headers. The techniques deal with missing Huffman tables and sub-sampling factors, estimate the resolution of fragments, assess the image quality of JPEG files with incorrect quantization tables, and create quantization tables that are very close to the correct quantization tables in a reasonable amount of time. Experiments with real camera pictures demonstrate that the techniques can recover standalone fragments accurately and efficiently.