Content based JPEG fragmentation point detection

In the forensics analysis of raw evidence data, fragmentation point detection is crucial to differentiate fragments of evidence and identify potentially corrupted data. This need is even more prominent for JPEG images since the chance is high that an erroneous data block passes a normal JPEG decoder without triggering any errors. Therefore, it is important to verify the content of the decoded image data to determine if fragmentation and/or corruption has occurred. In this paper, we propose three different techniques for the detection of fragmentation point based on the image contents, as well as a detector built by combining these methods. We evaluate the effectiveness of these techniques and the combined detector by implementing them on a standard JPEG decoder and testing them on more than 2000 fragmented images generated from over 1200 JPEG photos.