Steganalysis

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The Problem

Steganography is the art of hiding data in a given medium such that it cannot be detected by humans. It is a historic cryptographic technique that dates back to the Bacon cipher. Steganography has become relevant in today's world through the invention of lossy compression techniques. Two common lossy compression algorithms are the Joint Photographic Experts Group (JPEG) for images and MPEG Layer 3 (MP3) for sound. Both of these compression algorithms allow data to be hidden within them without introducing noticeable changes to the image or sound file. This has made it possible to transmit data between two parties in a covert manner that may appear as an innocent transmission. This has ramifications in the law enforcement world as steganography can be used to transmit terrorist or criminal communications without obvious detection.

Solution

Steganalysis is the research into detection of steganography within a given medium. Researchers have found statistical methods of determining whether a JPEG or MP3 file contains steganographic data. However, no tool current exists for law enforcement that uses these modern techniques. The Steganography Research Group is working on implementing the academic research into a product that can be readily used in a fast and accurate manner for law enforcement. The tool combines the work of several steganalysis techniques so that it can examine numerous JPEG and MP3 files and then report back to the investigator whether or not the file has hidden data. This then allows breaking of the file to commence so that the data may be extracted from the file.

Results

The Steganography Research Group is currently partnering with WetStone Technologies so that the JPEG and MP3 detection can be integrated with their steganography detection product in order to provide a coherent and consistent interface to law enforcement.

Support

This research is supported by the National Institute of Justice.