Informatica

A steganographic scheme based on perfect coverings of dichotomous shares with sparse observation windows is presented in this paper. The manipulations with pixels are based on the number of different colours in the sparse cells of the current observation window. The conditions for the existence of perfect coverings for different architectures of sparse observation windows are derived. The number and distribution of active cells in the current observation window contribute to the additional security of the proposed scheme. This paper also provides performance measures, statistical features, and demonstrates the robustness of the proposed steganographic scheme.

The JPEG image is the most popular file format in relation to digital images. However, up to the present time, there seems to have been very few data hiding techniques taking the JPEG image into account. In this paper, we shall propose a novel high capacity data hiding method based on JPEG. The proposed method employs a capacity table to estimate the number of bits that can be hidden in each DCT component so that significant distortions in the stego‐image can be avoided. The capacity table is derived from the JPEG default quantization table and the Human Visual System (HVS). Then, the adaptive least‐significant bit (LSB) substitution technique is employed to process each quantized DCT coefficient. The proposed data hiding method enables us to control the level of embedding capacity by using a capacity factor. According to our experimental results, our new scheme can achieve an impressively high embedding capacity of around 20% of the compressed image size with little noticeable degradation of image quality.