Description

Steganography refers to embedding information or secret message into media. This paper presents a simple and secure high – capacity steganographic algorithm for information hiding. We synthesize a cover -image texture which is increased in size according to user desire. The input texture is smaller in size and the texture is increased in size and resulting high resolution image is obtained. The secret information is placed in the high resolution image patches based on the look up table created. The created lookup table denotes the location of the secret information. The secret message is embedded in the images based on LSB replacement of the DCT coefficients of the cover image. The same process is reversed in the receiver side inorder to obtain the secret message and the original source patch. The performance of the process is measured based on the embedding capacity and other parameters. On the other hand, each byte of the secret information (secret Message, image, etc.) is first encrypted based on an exponential modular arithmetic which is then partitioned into two 4-bit words. Each 4-bit word represented as an integer value in is inserted into a pixel in the selected cover- image to form a stego image. The embedding capacity for an m by n cover-image could be as high as (m × n)/2, an experiment is illustrated for the proposed methodology. This prevents a visible seam while ensuring that the color style of significant parts of the selected region are preserved when pasting. Matting techniques are used to construct the weight map. Diffusion is performed using a framework of mean- value coordinates rather than solving the original Laplace equation. The benefits of this hybrid approach, compared to previous image composite method, are twofold. Firstly, since a gradient-based approach is used, it is unnecessary to extract an accurate matte, which allows user interaction to be much less precise.