Abstract: Images are transmitted through the internet for various purposes, such as confidential enterprise archives, document storage systems, medical imaging systems, and military applications. These images may contain secret or confidential information since it should be protected from leakage during transmissions. An approach for secure image transmission is needed, which is to transform a secret image into a meaningful Secret Fragment Mosaic Image with size almost same and looking similar to the preselected target image. The mosaic image is the outcome of arranging of the block fragments of a secret image in a way so as to disguise the other image called the target image. The mosaic image looks similar to a randomly selected target image. It is used for hiding of the secret image by color transforming their characteristics similar to the blocks of the target image. The appropriate information is embedded into the mosaic image for the recovery of the transmitted secret image.

Keywords: Color transformation, data hiding, mosaic image, covert communication.