On the capacity of stegosystems

ABSTRACT

Among the different applications where data hiding techniques can be used, one that has received huge attention in the last years is steganography. In that scenario, not just the embedded message is hidden, but the communication process itself is tried to be concealed. In spite of the numerous works in this field, the capacity of a perfect stegosystem (meaning a system where it is impossible to know if a given signal is watermarked or not) is still an open question in the data hiding community. In this paper we deal with the capacity of a discrete perfect stegosystem using some optimization procedures, and also present a lower-bound to the capacity of a perfect Gaussian stegosystem; interestingly this bound approaches the capacity of an AWGN channel (without host signal or the perfect steganography constraint) for small (compared with the power of the host) values of the embedding power. Furthermore, we apply the methodology used in this Gaussian scheme to a lattice-based embedding structure, introducing some promising results.

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INDEX TERMS

Primary Classification:
  K. Computing Milieux
  K.6 MANAGEMENT OF COMPUTING AND INFORMATION SYSTEMS
      K.6.5 Security and Protection (D.4.6, K.4.2)

Additional Classification:
  H. Information Systems
  H.1 MODELS AND PRINCIPLES
      H.1.1 Systems and Information Theory

General Terms:
Design, Theory

Keywords:
capacity, costa's construction, lattice, steganography