Modification in spatial, extraction from transform: Keyless side-information steganography for JPEG

The state of the art steganography approaches strictly assume that the receiver has access to a steganographic key. This limitation was mitigated for images in spacial domain, but the approach does not apply to JPEG images. In this paper, we introduce a keyless steganography scheme for JPEG images. Despite the spatial domain counterpart, our approach for the JPEG domain effectively preserves higher-order statistical models that are used in steganalysis. We show that our approach does not degrade image quality either. The proposed approach is a Side-Information (SI) steganography in the sense that its input is a never-compressed image. Another characteristic of the proposed approach is the separation of the embedding modification and data extraction domains, which can initiate further studies of similar approaches in the future.