Identification and recovery of JPEG files with missing fragments

Abstract

Recovery of fragmented files proves to be a challenging task for encoded files like JPEG. In this paper, we consider techniques for addressing two issues related to fragmented JPEG file recovery. First issue concerns more efficient identification of the next fragment of a file undergoing recovery. Second issue concerns the recovery of file fragments which cannot be linked to an existing image header or for which there is no available image header. Current file recovery approaches are not well suited to deal with these practical issues. In addressing these problems, we utilize JPEG file format specifications. More specifically, we propose a technique based on bit sequence matching to identify fragments created by the same Huffman code tables. We also address the construction of a pseudo header needed for recovery of stand-alone file fragments. Some experimental results are provided to support our claims. (C) 2009 Digital Forensic Research Workshop. Published by Elsevier Ltd. All rights reserved.