  The capacity and security of the confidential message on the channel are two
important challenges in steganography. In this paper, a new block steganography
model is presented using the bargain method so that a competitive model is
introduced. In this game, the blocks are the same players. The bargain is
provided with the aim of embedding information without reducing capacity as
well as increasing security. The proposed model shows that it can be used both
of the special domain and the transform domain, which are two important methods
of steganography. For this purpose, an example of a special domain model is
introduced in which, In the first step, the image is divided into $n \times n$
blocks, and in the second step using the graph coloring algorithm, pixels are
considered to embed confidential information in each block. In the third step,
regarding the bargaining method in game theory, each block plays the role of a
player, that the competition between players is based on the defined goal
function, and in the best blocks in terms of two criteria of capacity and
security, which here means each block has a higher security-to-capacity ratio,
so it has a higher priority, which is determined based on the bargaining model.
Also, information embedded in LSB two bits. An example of a conversion domain
method is also shows that security increases without decreasing in capacity.
The conclusion is evaluated by three criteria: PSNR, histogram, and
$\epsilon-secure$ also, 2000 standard images were evaluated and observed that
the proposed method improves the block methods of embedding information.
