Study On Information Hiding And Subliminal Channels

Steganography and subliminal channels are discussed in this thesis. Information hiding, steganography and subliminal channels have been introduced firstly; the basic theories of steganography are introduced systematically secondly; then a systematical summarization of the theories of subliminal channels and a deep research on the capacity of subliminal channels have been made; the design principle and design the procedure of a steganography scheme and its realization are given; finally a new threshold based steganography scheme for mobile commerce is proposed and its security is analyzed. The main results of this thesis are as follows: A systematical summarization of the theories of subliminal channels has been made. After a deep research on the capacity of subliminal channels has been made the definition of the subliminal capacity is given, some factors that reduce the capacity are discussed and the capacity of subliminal channels in ElGamal signatures is analyzed. Based on a systematical introduction of the theories of steganography a LSB steganography scheme in image has been designed and realized. The design principle and design the procedure of a steganography scheme and its realization are given and a necessary discussion is made. A new steganography scheme based on threshold is proposed. This scheme not only has some added security for introducing the threshold scheme but also significantly reduce the computing complexity and the requirements for the communication devices. So it enables clients to conduct mobile commerce transctions by carrying out steganographic communication. The security of the proposed scheme is also analyzed.