摘要

In traditional information hiding methods, the secret information is embedded into the carriers, which will inevitably leave traces of modification on the carriers. In those methods, the modified images can be easily detected by some steganalysis algorithm and thus the security can not be guaranteed. To address this problem, the concept of coverless information hiding is proposed. However, general coverless information hiding method has a lower information hiding capacity. In this paper, we propose a novel coverless information hiding method based on the average pixel values of sub-images. We generate hash sequences by a hashing algorithm and realize the secret information hiding through mapping relationship. In the first place, we build a dictionary and a hash array. Then we map the dictionary and the hash array through mapping relationship. Furthermore, we build a multi-level index structure for retrieving the stego-images efficiently. The experimental results and analysis show that our method has a good performance in the capacity of information hiding, the security, the robustness to image attacks and the hiding success rate based on different image databases.