  Coverless steganography has been a great interest in recent years, since it
is a technology that can absolutely resist the detection of steganalysis by not
modifying the carriers. However, most existing coverless steganography
algorithms select images as carriers, and few studies are reported on coverless
video steganography. In fact, video is a securer and more informative carrier.
In this paper, a novel coverless video steganography algorithm based on maximum
Direct Current (DC) coefficients is proposed. Firstly, a Gaussian distribution
model of DC coefficients considering video coding process is built, which
indicates that the distribution of changes for maximum DC coefficients in a
block is more stable than the adjacent DC coefficients. Then, a novel hash
sequence generation method based on the maximum DC coefficients is proposed.
After that, the video index structure is established to speed up the efficiency
of searching videos. In the process of information hiding, the secret
information is converted into binary segments, and the video whose hash
sequence equals to secret information segment is selected as the carrier
according to the video index structure. Finally, all of the selected videos and
auxiliary information are sent to the receiver. Especially, the subjective
security of video carriers, the cost of auxiliary information and the
robustness to video compression are considered for the first time in this
paper. Experimental results and analysis show that the proposed algorithm
performs better in terms of capacity, robustness, and security, compared with
the state-of-the-art coverless steganography algorithms.
