Development Trends in Steganography
  Steganography is a general term referring to all methods for the embedding of additional secret content into some form of carrier, with the aim of concealment of the introduced alterations. The choice of the carrier is nearly unlimited, it may be an ancient piece of parchment, as well as a network protocol header. Inspired by biological phenomena, adopted by man in the ancient times, it has been developed over the ages. Present day steganographic methods are far more sophisticated than their ancient predecessors, but the main principles have remained unchanged. They typically rely on the utilization of digital media files or network protocols as a carrier, in which secret data is embedded. This paper presents the evolution of the hidden data carrier from the ancient times till the present day and pinpoints the observed development trends, with special emphasis on network steganography. 
Elzbieta Zielinska, Wojciech Mazurczyk and Krzysztof Szczypiorski
cs.MM