101 research outputs found
Using Transcoding for Hidden Communication in IP Telephony
The paper presents a new steganographic method for IP telephony called
TranSteg (Transcoding Steganography). Typically, in steganographic
communication it is advised for covert data to be compressed in order to limit
its size. In TranSteg it is the overt data that is compressed to make space for
the steganogram. The main innovation of TranSteg is to, for a chosen voice
stream, find a codec that will result in a similar voice quality but smaller
voice payload size than the originally selected. Then, the voice stream is
transcoded. At this step the original voice payload size is intentionally
unaltered and the change of the codec is not indicated. Instead, after placing
the transcoded voice payload, the remaining free space is filled with hidden
data. TranSteg proof of concept implementation was designed and developed. The
obtained experimental results are enclosed in this paper. They prove that the
proposed method is feasible and offers a high steganographic bandwidth.
TranSteg detection is difficult to perform when performing inspection in a
single network localisation.Comment: 17 pages, 16 figures, 4 table
Multi-Level Steganography: Improving Hidden Communication in Networks
The paper presents Multi-Level Steganography (MLS), which defines a new
concept for hidden communication in telecommunication networks. In MLS, at
least two steganographic methods are utilised simultaneously, in such a way
that one method (called the upper-level) serves as a carrier for the second one
(called the lower-level). Such a relationship between two (or more) information
hiding solutions has several potential benefits. The most important is that the
lower-level method steganographic bandwidth can be utilised to make the
steganogram unreadable even after the detection of the upper-level method:
e.g., it can carry a cryptographic key that deciphers the steganogram carried
by the upper-level one. It can also be used to provide the steganogram with
integrity. Another important benefit is that the lower-layer method may be used
as a signalling channel in which to exchange information that affects the way
that the upper-level method functions, thus possibly making the steganographic
communication harder to detect. The prototype of MLS for IP networks was also
developed, and the experimental results are included in this paper.Comment: 18 pages, 13 figure
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