MP3 Steganography Techniques

The MP3 audio encoding format is currently one of the most popular encoding formats in use. On average, it takes significantly less space to store than, for example, a PCM-encoded WAV file, even though it retains most of the original, uncompressed audio information. Most users of MP3 files are unaware that they can be used as carriers of steganographically-hidden information. Although it has not yet been greatly explored, there are various types of steganography techniques that exist which allow for the hiding of information within MP3 files of any type. Two of the techniques the authors studied include those implemented by MP3Stego developed by Fabien Petitcolas and MP3Stegazaurus by former Illinois Institute of Technology student Mikhail Zaturenskiy. The technique implemented by MP3Stego performs the injection of covert information during the encoding process, while the technique implemented by MP3Stegazaurus uses areas of an already-existing MP3 file known to be skipped or ignored by MP3 playing and decoding applications to store covert information. The authors have developed a tool which implements a technique allowing for the hiding of covert information within the audio information-containing portions of an MP3 file in a way that does not yet appear to have been explored. Unlike the technique implemented by MP3Stego, which involves hiding information within the audio information-containing portions of an MP3 file during the encoding process, this new technique involves hiding it after the encoding process has already taken place. This paper details the research carried out by the authors as well as how the tool that makes use of this technique works.