Coverless Image Steganography Without Embedding

The traditional image steganography technologies designate a cover image and embed secret data into it to form the stego-image. However, the modification traces caused by the embedding will be left in the cover image, which makes successful steganalysis possible. To fundamentally address this issue, this paper proposes a novel image steganography framework, called as coverless image steganography, which does not need to employ the designated cover image for embedding the secret data. In this framework, a series of appropriate original images which already contain the secret data are directly chosen from a constructed database, and these original images can be regarded as the stego-images. Firstly, a number of images are collected to construct the database, and these images are indexed according to their hash sequence generated by a robust hashing algorithm. Then, the secret data is transformed to a bit string and divided into a number of segments. To implement the information hiding, the images of which the hash sequences are the same as the segments are chosen from the database as the stego-images. Experimental results show that the proposed coverless image steganography framework can resist the existing steganalysis tools, and have desirable robustness to the typical image attacks such as rescaling, luminance change, and noise adding.