| In this paper, an algorithm which can efficiently carve messy JPEG files in disk was developed to recover JPEG files on NAND devices. To achieve this goal, existing JPEG carving methods, such as simple carving, smart carving and carving with graph theory was dialectically assessed and contrasted. Through the comparison, the limitations of the existing JPEG carving methods and challenges brought by NAND devices were clarified.The difference between the NAND devices and the traditional storage devices was analyzed mainly on the link between the file system and the physical hardware. According to the JPEG standard, a carving algorithm which made the utmost of JPEG compressed data was presented after analyzing the internal structure and the content feature. Moreover, multiple preprocess method was applied to the file system data to reduce the complexity of the compute.To verify the accuracy of the carving algorithm, detailed experimental procedure on multiple experimental data sets was conducted and analyzed. It was showed that this carving algorithm was effective to recover the completely disordered and fragmentized JEPG files on NAND flash devices. |
