Abstract: In order to further improve the security of adaptive steganography algorithms, this article introduces the idea of image blocking, rewrites the distortion function of the original J-UNIWARD algorithm, and changes additive distortion functions to non-additive distortion functions. The implementation process of the algorithm is as follows: The carrier image to be processed is divided into four sub-blocks, and the texture complexity of each sub-block is calculated separately, under the constraint of keeping total embedding amount unchanged. The more complex blocks are preferentially chosen to be embedded. By recalculating the distortion function after each block-embedding, the embedding amount is dynamically adjusted according to the complexity. Then the secret information is adaptively embed into the texture area by STC (syndrome trelliscodes) encoding. Finally, detection performance is analyzed by using DCTR and ccJRM steganalysis techniques. Experimental results show that under the same capacity, the proposed algorithm can significantly improve the anti-stealth analysis ability of the algorithm.

Key words: divided into blocks, texture complexity, non-additive distortion, STC encoding, steganography